What affects PNG size
PNG compresses pixel data without losing it. Solid colors and repeated patterns can encode compactly; noisy photographs often produce large PNGs because every detailed pixel must be represented accurately. Lossless PNG compression preserves decoded pixels, but the amount saved depends on how the original was encoded.
A dedicated PNG optimizer can reduce bytes by choosing color palettes and filter strategies. Basic browser canvas re-encoding typically does not run those same optimization passes, so this PNG compressor may produce a file that is the same size or larger.
Try WebP where it fits
WebP supports transparency and can store photographic images much more compactly. Lossy WebP may change pixels, so inspect thin lines, small lettering and transparent edges before publishing.
For an exact screenshot, diagram or editing master, keep a PNG copy. Reduce dimensions to the actual use size and compare the encoded file before replacing anything.
Frequently asked questions
Why did my PNG get larger?
The canvas encoder may use a different compression strategy, and PNG files with complex photographic detail are difficult to shrink without pixel changes.