PNG is the safe format for logos, screenshots, UI graphics and cutout product images because it is lossless and supports transparency. The downside is file size. A transparent product cutout or high-resolution screenshot can easily be several megabytes, especially if it contains many colors.
The wrong fix is converting every PNG to JPG. JPG may shrink the file, but it removes transparency and can make text edges fuzzy. If the image needs to sit on different backgrounds, you need to keep the alpha channel intact while reducing unnecessary pixel data.
Start with dimensions
Before compression, check whether the PNG is larger than it will ever be displayed. A 3000-pixel transparent logo used at 300 pixels wide is wasting space. Resize it to the largest real display size, plus a retina buffer if needed. This can reduce file size more than compression alone.
For screenshots, crop irrelevant browser chrome or empty space. PNG compresses flat areas well, but it still has to store every pixel. Removing unused borders, shadows and huge transparent padding can make a surprising difference.
Keep PNG or use WebP when allowed
If the destination supports WebP, converting a transparent PNG to WebP can produce a much smaller file while preserving transparency. This is often ideal for websites. If the destination specifically requires PNG, use PNG compression and resizing, not JPG conversion.
After compressing, place the file on both light and dark backgrounds to confirm the edges still look clean. Transparent images can hide problems on white pages. Checking against contrast reveals halos, jagged masks or accidental white fills before you publish.