Why WebP gets rejected
WebP is common on modern websites, but many upload fields still list only JPG, PNG, or PDF as accepted file types.
This usually is not a problem with your image. The destination simply has a narrower compatibility list.
JPG or PNG?
Convert WebP to JPG for photos and marketplace images. Convert WebP to PNG when you need transparency, screenshots, graphics, or image editing.
Quality checklist
If the WebP had transparency, JPG will flatten it. Use PNG when transparent areas matter. Check the converted file before uploading it anywhere important.