PNG Compressor Online

PNG (Portable Network Graphics) is a lossless raster format designed for images that require pixel-perfect accuracy, such as screenshots, UI mockups, diagrams, logos with transparency, and any graphic with text or sharp edges. Unlike JPEG, PNG preserves every pixel exactly as authored, which makes it the go-to choice when fidelity matters more than file size. The downside is that PNG files are often considerably larger than JPEGs for photographic content. PNG supports full alpha-channel transparency, 24-bit and 48-bit color depths, and metadata like gamma correction, making it versatile across operating systems and browsers.

SizeSnap compresses PNGs through a two-pronged approach. First, it applies quantization — intelligently reducing the color palette from millions of colors down to an optimal subset — while preserving transparency and visual fidelity. The encoder then uses maximum-level DEFLATE compression with optimized filtering strategies to squeeze every byte from the resulting image. A binary search over the palette size and quantization quality finds the combination that lands closest to your exact target size. This lets SizeSnap deliver dramatic reductions (often 60–80%) on screenshots and UI graphics while keeping text crisp, edges clean, and transparent areas intact.

• 1Screenshots with large flat-color areas (like IDE or terminal captures) compress extremely well — you can often target 30–40% of the original and see no visible difference.
• 2If your PNG is a photo (not a graphic), consider converting to JPEG first. JPEG is far more efficient for photographic content, and SizeSnap can compress JPEGs to any target size.
• 3Transparent PNGs compress best when the transparent region is uniform. Avoid semi-transparent gradients in large areas if file size is a concern.
• 4Remove unnecessary metadata (EXIF, color profiles) before compressing. SizeSnap strips metadata automatically during compression.
• 5For web use, target under 200 KB per image. Larger PNGs slow down page loads and hurt Core Web Vitals scores, especially on mobile connections.

Can PNG be compressed without losing quality?

SizeSnap uses palette quantization to reduce PNG file sizes. While technically lossy, the visual difference is usually imperceptible for screenshots and graphics.

Should I use PNG or JPEG for my image?

Use PNG for screenshots, graphics with text, logos, and images needing transparency. Use JPEG for photographs and images with smooth color gradients.

Why is my PNG file so large?

PNGs store every pixel exactly, which makes them large for photographic content. Screenshots and graphics with flat colors compress much better in PNG format.

Does compression preserve transparency?

Yes, SizeSnap preserves alpha-channel transparency when compressing PNG files.