压缩图像是一种形式图像优化.目标是实现最小文件大小,但视觉质量不损保存字节提高网站性能 因为图像文件越小浏览器下载越快选择压缩格式时,应考虑图像类型、目的和特征失压缩最适合照片和复杂图像,无损压缩最适合标识和简单图像
文章中:
- PHP压缩优化图像
- PHP函数压缩图像扩展库
- 压缩图片云化PHP图像API
- hp图像选择压缩格式
快速图像加载网站 访问者返回的可能性越大 产生更高的转换率半数访问者期望网站二秒内加载Akamai和Gomez的调查显示
- 长度加载时间是放弃页的一个主要推理,越多加加载时间越多的可能性越大近40%访问者后放弃页面三秒.
- 73%移动用户在其设备上经历负载时间问题
- 延时一秒可使访问者满意度下降16%,导致转换率下降7%或更高
PHP图像压缩方式
- PHP内置函数,例如
imagejpeg路径输出图像和质量规范安装PHPGD图形库 - 通过PHP图像优化PiotrSliwa所建PHP库,OptiPNG,
样数并jpegoptim](http://jpegclub.org/jpegtran/)图像优化程序可压缩图像文件10-70%而不牺牲视觉吸引力 - 随身带PHP图像缓存简单PHP类压缩图像PHP图像压缩完成后,图像缓存缓存浏览器中图像并返回图像新源
- 带虚构本地PHP扩展使用图像MagickAPI.
Cloudinary系统可高效优化媒体资产-不论编程语言原因之一是默认云性自动在所有变换图像上执行某些优化步骤++通过内容传输网络实现集成快速传输能力确保图像无缝显示在查看器设备上点击这里要求免费永久云式账号
云化提供以下图像压缩能力:
自动质量调整编码后你加
q_aut参数到图像URL,云化选择最优质量压缩级别和编码设置结果为压缩图像高视觉素养参见此示例 :
微调图像自动化质量
q_aut:best.q_auto:low,q_auto:g或q_ato:eco参数随心所欲自动格式化:添加
f_aut参数到图像URLs使云化图像最优格式化在大多数情况下, Chrome用户会接收WEP.web)!互联网探索者用户JPEG-XR.jxr)!搜索用户JPEG2000浏览器不支持这些格式中的任何格式时,云性以文件扩展描述格式交付图像万一你加二
f_aut并q_autJPEG图像的URL参数云性自动化质量算法停止chroma子采样,保留JPEG格式而不切换WebP质量保护,因为损微webP格式总能实现Chroma子采样,这可能会降低图像视觉质量大小裁剪:通过添加宽度
华府和高度h参数到他们的 URLs,你可用云性调整图像大小,例如:<\/Image>","codeSnippet":" \n\t
\n<\/Image>","status":0,"statusText":"Ok","displayName":"React","packageName":"cloudinary-react","packageStatus":"","packageVersion":"1.x"},{"sdkId":"vue_2","framework":"vue_2","language":"vue","rawCodeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().width(0.5));","codeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().width(0.5));","status":0,"statusText":"Ok","displayName":"Vue.js","packageName":"@cloudinary\/vue","packageStatus":"","packageVersion":"1.x"},{"sdkId":"vue","framework":"vue","language":"vue","rawCodeSnippet":" <\/cld-image>","codeSnippet":" \n\t \n<\/cld-image>","status":0,"statusText":"Ok","displayName":"Vue.js","packageName":"cloudinary-vue","packageStatus":"legacy","packageVersion":"1.x"},{"sdkId":"angular_2","framework":"angular_2","language":"angular","rawCodeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().width(0.5));","codeSnippet":"new 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\"scale\"}).toHtml();","codeSnippet":"cloudinary.imageTag('sample.jpg', {width: \"0.5\", crop: \"scale\"}).toHtml();","status":0,"statusText":"Ok","displayName":"JS","packageName":"cloudinary-core","packageStatus":"legacy","packageVersion":"2.x"},{"sdkId":"python","framework":"python","language":"python","rawCodeSnippet":"CloudinaryImage(\"sample.jpg\").image(width=\"0.5\", crop=\"scale\")","codeSnippet":"CloudinaryImage(\"sample.jpg\").image(width=\"0.5\", crop=\"scale\")","status":0,"statusText":"Ok","displayName":"Python","packageName":"cloudinary","packageStatus":"","packageVersion":"1.x"},{"sdkId":"php_2","framework":"php_2","language":"php","rawCodeSnippet":"(new ImageTag('sample.jpg'))\n\t->resize(Resize::scale()->width(0.5));","codeSnippet":"(new ImageTag('sample.jpg'))\n\t->resize(Resize::scale()->width(0.5));","status":0,"statusText":"Ok","displayName":"PHP","packageName":"cloudinary_php","packageStatus":"","packageVersion":"2.x"},{"sdkId":"php","framework":"php","language":"php","rawCodeSnippet":"cl_image_tag(\"sample.jpg\", array(\"width\"=>\"0.5\", \"crop\"=>\"scale\"))","codeSnippet":"cl_image_tag(\"sample.jpg\", array(\"width\"=>\"0.5\", \"crop\"=>\"scale\"))","status":0,"statusText":"Ok","displayName":"PHP","packageName":"cloudinary_php","packageStatus":"legacy","packageVersion":"1.x"},{"sdkId":"java","framework":"java","language":"java","rawCodeSnippet":"cloudinary.url().transformation(new Transformation().width(0.5).crop(\"scale\")).imageTag(\"sample.jpg\");","codeSnippet":"cloudinary.url().transformation(new 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cloudinary)","codeSnippet":"imageView.cldSetImage(cloudinary.createUrl().setTransformation(CLDTransformation().setWidth(0.5).setCrop(\"scale\")).generate(\"sample.jpg\")!, cloudinary: cloudinary)","status":0,"statusText":"Ok","displayName":"iOS","packageName":"cloudinary","packageStatus":"","packageVersion":"3.x"},{"sdkId":"android","framework":"android","language":"android","rawCodeSnippet":"MediaManager.get().url().transformation(new Transformation().width(0.5).crop(\"scale\")).generate(\"sample.jpg\");","codeSnippet":"MediaManager.get().url().transformation(new Transformation().width(0.5).crop(\"scale\")).generate(\"sample.jpg\");","status":0,"statusText":"Ok","displayName":"Android","packageName":"cloudinary-android","packageStatus":"","packageVersion":"1.x"},{"sdkId":"flutter","framework":"flutter","language":"flutter","rawCodeSnippet":"cloudinary.image('sample.jpg').transformation(Transformation()\n\t.resize(Resize.scale().width(0.5)));","codeSnippet":"cloudinary.image('sample.jpg').transformation(Transformation()\n\t.resize(Resize.scale().width(0.5)));","status":0,"statusText":"Ok","displayName":"Flutter","packageName":"cloudinary_flutter","packageStatus":"","packageVersion":"0.x"},{"sdkId":"kotlin","framework":"kotlin","language":"kotlin","rawCodeSnippet":"cloudinary.image {\n\tpublicId(\"sample.jpg\")\n\t resize(Resize.scale() { width(0.5F) }) \n}.generate()","codeSnippet":"cloudinary.image {\n\tpublicId(\"sample.jpg\")\n\t resize(Resize.scale() { width(0.5F) }) \n}.generate()","status":0,"statusText":"Ok","displayName":"Kotlin","packageName":"kotlin-url-gen","packageStatus":"","packageVersion":"1.x"},{"sdkId":"jquery","framework":"jquery","language":"jquery","rawCodeSnippet":"$.cloudinary.image(\"sample.jpg\", {width: \"0.5\", crop: \"scale\"})","codeSnippet":"$.cloudinary.image(\"sample.jpg\", {width: \"0.5\", crop: \"scale\"})","status":0,"statusText":"Ok","displayName":"jQuery","packageName":"cloudinary-jquery","packageStatus":"","packageVersion":"2.x"},{"sdkId":"react_native","framework":"react_native","language":"react_native","rawCodeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().width(0.5));","codeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().width(0.5));","status":0,"statusText":"Ok","displayName":"React Native","packageName":"cloudinary-react-native","packageStatus":"","packageVersion":"0.x"}]" parsed-url="{"url":"https:\/\/res.www.aaaalireno.com\/demo\/image\/upload\/w_0.5\/sample.jpg","cloud_name":"demo","host":"res.www.aaaalireno.com","type":"upload","resource_type":"image","transformation":[{"width":"0.5"}],"transformation_string":"w_0.5","url_suffix":"","version":"","secure":true,"public_id":"sample.jpg","extension":"jpg","format":"jpg","format_code":true,"signature":"","private_cdn":false,"result_asset_type":"image"}" with-url="true" > 加载代码示例 
<\/Image>","codeSnippet":" \n\t
\n<\/Image>","status":0,"statusText":"Ok","displayName":"React","packageName":"cloudinary-react","packageStatus":"","packageVersion":"1.x"},{"sdkId":"vue_2","framework":"vue_2","language":"vue","rawCodeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().height(200));","codeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().height(200));","status":0,"statusText":"Ok","displayName":"Vue.js","packageName":"@cloudinary\/vue","packageStatus":"","packageVersion":"1.x"},{"sdkId":"vue","framework":"vue","language":"vue","rawCodeSnippet":" <\/cld-image>","codeSnippet":" \n\t \n<\/cld-image>","status":0,"statusText":"Ok","displayName":"Vue.js","packageName":"cloudinary-vue","packageStatus":"legacy","packageVersion":"1.x"},{"sdkId":"angular_2","framework":"angular_2","language":"angular","rawCodeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().height(200));","codeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().height(200));","status":0,"statusText":"Ok","displayName":"Angular","packageName":"@cloudinary\/ng","packageStatus":"","packageVersion":"1.x"},{"sdkId":"angular","framework":"angular","language":"angular","rawCodeSnippet":" <\/cl-transformation> <\/cl-image>","codeSnippet":" \n\t \n\t<\/cl-transformation>\n<\/cl-image>","status":0,"statusText":"Ok","displayName":"Angular","packageName":"@cloudinary\/angular-5.x","packageStatus":"legacy","packageVersion":"1.x"},{"sdkId":"js_2","framework":"js_2","language":"js","rawCodeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().height(200));","codeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().height(200));","status":0,"statusText":"Ok","displayName":"JS","packageName":"@cloudinary\/url-gen","packageStatus":"","packageVersion":"1.x"},{"sdkId":"js","framework":"js","language":"js","rawCodeSnippet":"cloudinary.imageTag('sample.jpg', {height: 200, crop: \"scale\"}).toHtml();","codeSnippet":"cloudinary.imageTag('sample.jpg', {height: 200, crop: \"scale\"}).toHtml();","status":0,"statusText":"Ok","displayName":"JS","packageName":"cloudinary-core","packageStatus":"legacy","packageVersion":"2.x"},{"sdkId":"python","framework":"python","language":"python","rawCodeSnippet":"CloudinaryImage(\"sample.jpg\").image(height=200, crop=\"scale\")","codeSnippet":"CloudinaryImage(\"sample.jpg\").image(height=200, crop=\"scale\")","status":0,"statusText":"Ok","displayName":"Python","packageName":"cloudinary","packageStatus":"","packageVersion":"1.x"},{"sdkId":"php_2","framework":"php_2","language":"php","rawCodeSnippet":"(new ImageTag('sample.jpg'))\n\t->resize(Resize::scale()->height(200));","codeSnippet":"(new 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Transformation().height(200).crop(\"scale\")).imageTag(\"sample.jpg\");","status":0,"statusText":"Ok","displayName":"Java","packageName":"cloudinary","packageStatus":"","packageVersion":"1.x"},{"sdkId":"ruby","framework":"ruby","language":"ruby","rawCodeSnippet":"cl_image_tag(\"sample.jpg\", :height=>200, :crop=>\"scale\")","codeSnippet":"cl_image_tag(\"sample.jpg\", :height=>200, :crop=>\"scale\")","status":0,"statusText":"Ok","displayName":"Ruby","packageName":"cloudinary","packageStatus":"","packageVersion":"1.x"},{"sdkId":"csharp","framework":"csharp","language":"csharp","rawCodeSnippet":"cloudinary.Api.UrlImgUp.Transform(new Transformation().Height(200).Crop(\"scale\")).BuildImageTag(\"sample.jpg\")","codeSnippet":"cloudinary.Api.UrlImgUp.Transform(new 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cloudinary)","codeSnippet":"imageView.cldSetImage(cloudinary.createUrl().setTransformation(CLDTransformation().setHeight(200).setCrop(\"scale\")).generate(\"sample.jpg\")!, cloudinary: cloudinary)","status":0,"statusText":"Ok","displayName":"iOS","packageName":"cloudinary","packageStatus":"","packageVersion":"3.x"},{"sdkId":"android","framework":"android","language":"android","rawCodeSnippet":"MediaManager.get().url().transformation(new Transformation().height(200).crop(\"scale\")).generate(\"sample.jpg\");","codeSnippet":"MediaManager.get().url().transformation(new Transformation().height(200).crop(\"scale\")).generate(\"sample.jpg\");","status":0,"statusText":"Ok","displayName":"Android","packageName":"cloudinary-android","packageStatus":"","packageVersion":"1.x"},{"sdkId":"flutter","framework":"flutter","language":"flutter","rawCodeSnippet":"cloudinary.image('sample.jpg').transformation(Transformation()\n\t.resize(Resize.scale().height(200)));","codeSnippet":"cloudinary.image('sample.jpg').transformation(Transformation()\n\t.resize(Resize.scale().height(200)));","status":0,"statusText":"Ok","displayName":"Flutter","packageName":"cloudinary_flutter","packageStatus":"","packageVersion":"0.x"},{"sdkId":"kotlin","framework":"kotlin","language":"kotlin","rawCodeSnippet":"cloudinary.image {\n\tpublicId(\"sample.jpg\")\n\t resize(Resize.scale() { height(200) }) \n}.generate()","codeSnippet":"cloudinary.image {\n\tpublicId(\"sample.jpg\")\n\t resize(Resize.scale() { height(200) }) \n}.generate()","status":0,"statusText":"Ok","displayName":"Kotlin","packageName":"kotlin-url-gen","packageStatus":"","packageVersion":"1.x"},{"sdkId":"jquery","framework":"jquery","language":"jquery","rawCodeSnippet":"$.cloudinary.image(\"sample.jpg\", {height: 200, crop: \"scale\"})","codeSnippet":"$.cloudinary.image(\"sample.jpg\", {height: 200, crop: \"scale\"})","status":0,"statusText":"Ok","displayName":"jQuery","packageName":"cloudinary-jquery","packageStatus":"","packageVersion":"2.x"},{"sdkId":"react_native","framework":"react_native","language":"react_native","rawCodeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().height(200));","codeSnippet":"new CloudinaryImage(\"sample.jpg\").resize(scale().height(200));","status":0,"statusText":"Ok","displayName":"React Native","packageName":"cloudinary-react-native","packageStatus":"","packageVersion":"0.x"}]" parsed-url="{"url":"https:\/\/res.www.aaaalireno.com\/demo\/image\/upload\/h_200\/sample.jpg","cloud_name":"demo","host":"res.www.aaaalireno.com","type":"upload","resource_type":"image","transformation":[{"height":"200"}],"transformation_string":"h_200","url_suffix":"","version":"","secure":true,"public_id":"sample.jpg","extension":"jpg","format":"jpg","format_code":true,"signature":"","private_cdn":false,"result_asset_type":"image"}" with-url="true" > 加载代码示例 
云形保持宽度比,但调整图像大小与你指定的高度
\n\t
云形支持多图像编织模式尺度化,适配,适配,填充,填充,限值,程序板,lPad系统,mad,裁剪,缩略图,imagga_crop并imagga标度.
关于选择压缩格式图像时,重要的是考虑你处理的内容类型。不同的压缩算法提供图像质量和文件大小之间的各种取舍
取右格式图片指南如下:
- JPEG:这是照片和复杂图像最常用格式,多细节多色JPEG提供损压缩值,意指某些图像数据会丢失,但通常无法察觉云化可自动设置压缩级别保留视觉质量,同时将文件尺寸减到最小值
- PNG:图像理想带平面区,如标识或文本图形PNG无损压缩格式,保存所有图像数据可产生较大文件大小,但图像质量保留
- WebP:这是一个更新格式,提供损耗和无损压缩webP往往生成比JPEG和PNG小文件相似水平视觉质量并非所有浏览器都完全支持WBP,但用云形系统,WBP可动态服务给拥有支持浏览器的访问者。
- SVG文件独立解析, 意指它们看各种大小SVG不适合照相
压缩图像时需要考虑一些重要因素
- 图片内容:如前所述,JPEG或WebP通常最有效使用,而PNG或SVG类简单图像效果更好
- 浏览器支持:总要检查选择格式与浏览器范围相容性,期望访问者使用或用云化动态为每个用户提供最合适的图像
- 装入时间: 视用户网络速度而定, 小文件通常会加速加载时间浏览器工具测试图片以各种格式加载需要多长时间
- 质量需求:某些图像可能需要更高质量,因为它们包含复杂细节或文本在这些例子中,可能值得接受质量更高的图像大文件尺寸
适当优化并缓存图像是提高网站性能的关键步骤小技巧这个文章提供只是一个开始查看云文件更多思想JPEG图像优化而无损质量并发图像变换.
