WPCLipart.com
image file formats in use at WPClipart
PNG
This is the "default", or at least, most comon filetype available. It lends itself well to solid colors often found in clip art, without being lossy. Often can be "indexed", meaning limiting the amount of colors, therefore lowering file size. However, that feature does not work well for gradients, as often found in photographs.
AVIF
AV1 Image is the newest/hot format. Smaller yet more efficient than even the WebP. Already supported in the latest Chrome and Edge Browsers. Also available on Firefox if enabled. Go to "about:config", search for image.avif.enabled, and double-click to set as true. See: https://winaero.com/enable-avif-support-in-mozilla-firefox/ if you need some help :-)
T-PNG
This simply means a PNG with an alpha channel, meaning transparent. This is needed when pasting images together or over parts of other elements. To differentiate them from the regular PNG files here at WPCLipart, the filename for transparent PNGs always end as:
"_T.png"
JPG
JPGs are especially efficient for photographs, or anything with gradients. If a bit lossy, they can trim filesize. Can also be used everyplace, even for Facebook and just about anyplace that allows uploaded images.
SVG
Vector format. If you want to be able to scale an image without any loss is sharpness, this is the format you want.
webP
Is a file format pushed by Google. It is a bit lossy but has better compression ratios (smaller file sizes) than JPGs. Can also have transparency like a PNG. Will it replace JPG and/or PNG? I guess it's possible.