A WordPress library can use several formats. Keep editing originals and choose delivery files for each use.
Check which formats your WordPress installation, theme, plugins and image-processing library accept. Keep original files, upload a small sample, and inspect thumbnails and responsive variants before replacing a library. Pre-conversion does not guarantee that the CMS will avoid further processing.
JPEG is useful for photographs and workflows that require JPG. It uses lossy encoding and cannot retain transparency; transparent areas are exported on white. PNG is useful for text, screenshots, sharp edges and transparency. PNG losslessly encodes only the pixel buffer Canvas renders. Browser decoding, color conversion or bit-depth handling can change source pixels; profiles and metadata may differ.
WebP can be useful for web delivery and supports transparency. The WebP format can store animation, but this tool exports one still frame from animated inputs; animation is not preserved. This tool passes a quality value to the browser encoder. A quality setting of 100 does not guarantee lossless WebP output; download and inspect the result. AVIF can offer efficient compression, depending on the source and encoder. Reading AVIF and writing AVIF are separate browser capabilities. An unavailable output format cannot be exported by this tool.
Set width and height or CSS aspect-ratio so the page can reserve space. Use responsive image sizes where appropriate. Load the main image promptly and consider lazy-loading images below the fold. Measure the published page on mobile; a format change alone does not guarantee better LCP, CLS or INP.
Compare JPEG, PNG, WebP and AVIF by content type, transparency, compatibility and editing needs.
Use the original and a downloaded sample to judge the tradeoff. There is no fixed compression saving that applies to every image.
Use the original and a downloaded sample to judge the tradeoff. There is no fixed compression saving that applies to every image.
Use the original and a downloaded sample to judge the tradeoff. There is no fixed compression saving that applies to every image.
Practical guides for local conversion, image delivery, accessibility and choosing formats for a website.
Compare a WebP export with the PNG original before choosing the delivery format.
Image optimization supports accessibility and loading performance. Ranking gains cannot be promised.
A WordPress library can use several formats. Keep editing originals and choose delivery files for each use.
