Resize images

With our method — half-step reduction when the factor exceeds 2× — quality matches professional tools. We measured it: going from 1920 to 200 px gives an error of 3.5 out of 255 against a reference resampling, in all three browsers. A compressed JPG may lose a little through re-encoding, but the new resolution is clean.

Yes, this is one of the main use cases. Resize photos to 1920 px, or your design width, before uploading to your site. Then run them through Compress image to cut the weight further.

Yes. PNG and WebP keep transparency completely when resizing, partial transparency included: a soft edge comes back with its values intact.

16384 pixels per side. It is a browser technical limit, not one we chose: asking for more produces a blank image, because the canvas accepts the size and then doesn’t draw. For larger dimensions, use a specialized desktop tool.

That is what Convert images does: it moves between JPG, PNG, WebP and ICO. Resizing keeps the source format, except where the browser can’t write it — a BMP comes out as PNG and an AVIF as WebP, and the card tells you so.

Yes, with one nuance: an SVG is vector art with no natural dimensions, so we ask for the base size to rasterize at. If you didn’t say, each browser would invent a different one. The result is delivered as PNG.