Save for Web in Paint by Zaweba: smaller files, same look

A web page loads only as fast as its heaviest picture. File > Save for Web in Paint by Zaweba is built for one job: getting an image as small as possible while it still looks right. It does that with side-by-side previews, palette controls for PNG-8 and GIF, AVIF output, an option to optimise to a target size, and a switch for whether File Info goes with the file.

Comparing side by side

The 2-Up and 4-Up previews show your original next to one or three compressed versions. This is the heart of the dialog. Rather than guessing at a quality number, you look at the picture in each version and pick the smallest one where you can't see a difference that matters.

Zoom in on the parts that suffer first: fine text, faces, smooth skies and hard edges against flat colour. Those are where compression shows its seams.

PNG-8 and GIF

PNG-8 and GIF store a limited palette of colours, and both can be surprisingly small for graphics. Paint by Zaweba offers perceptual, selective and adaptive reduction methods for choosing the palette. Perceptual favours colours the eye is sensitive to. Selective leans towards broad areas of colour and colours that matter on the web. Adaptive takes its palette from the most common colours in the image. For logos and icons, try selective or adaptive and lower the colour count until something breaks, then step back up.

Lossy smoothing trades a little accuracy for a smaller file by letting similar pixels match more often. A small amount often goes unnoticed on graphics with gradients.

AVIF and target size

AVIF is a modern format that usually beats JPEG on size at the same visual quality, especially on photographs. Most current browsers display it, so it is a good choice for large hero images and product photos on your own site.

Optimise to a target size flips the question round. Instead of choosing a quality and seeing what size comes out, you say how big the file may be, and Paint by Zaweba works out the settings to hit it. That is very useful when a platform has a strict upload limit, or when you are bringing a whole page under a weight budget.

File Info on or off

File Info is the metadata you can attach with File > File Info: title, author, copyright and more. For a web image you may want it, so your copyright travels with the picture, or you may want to strip it to save a few bytes and avoid publishing details such as GPS coordinates. Save for Web lets you choose for each export.

Habits for lean pages

Resize before you compress. A 4000-pixel photo shown at 1200 pixels wastes most of its bytes, and no compression setting fixes that. Resize or crop the picture first, then open Save for Web.

Match format to content. Photographs go to JPEG or AVIF. Flat graphics with few colours go to PNG-8 or GIF. Graphics that need smooth transparency usually want full PNG. Use the 4-Up view to test that rule rather than trusting it blindly.

Keep your layered master. Save for Web writes a copy, so the .ptx stays at full quality for the next version. Paint by Zaweba does all of this offline, without uploading your pictures to an online compressor.