PNG vs JPG vs WebP: which format should you actually use?
Reviewed July 28, 2026
Boltpic
Each guide describes the current Boltpic tools and links to relevant technical references. Results that depend on the image, browser, or device are identified as variable.
The same image can look and weigh very different as PNG, JPG, or WebP. The exact result depends on its detail, output dimensions, encoder, and quality setting, so one set of benchmark numbers cannot describe every file.
WebP is often a sensible starting point, but it is not automatic. Check what the image contains first: transparency, fine text, and photographic detail each reward a different choice.
How each format compresses an image
JPG is lossy. It splits the image into 8 × 8 pixel blocks and reduces detail your eyes are less likely to notice — subtle variations in smooth areas and fine texture in shadows. That suits photographs, but discarded information does not return and repeated re-encoding compounds artifacts. Keep an editing original and export the delivery copy once.
PNG supports lossless compression and alpha transparency. It preserves text, lines, and flat-color screenshots cleanly, but a photograph with complex color variation will often be larger than a lossy alternative.
WebP supports lossy and lossless compression as well as transparency. It often produces a smaller photograph than a visually similar JPG and can be an alternative to PNG for transparent graphics. Current major browsers support it, but an external upload service may not.
Where JPG still earns its keep
JPG's advantage is broad compatibility. It is a practical candidate for email attachments, documents, and uploads whose requirements are unclear. If the destination specifies a format or limit, follow that requirement first.
Its weaknesses are clear: no transparency, and hard edges such as text or line art can develop ringing. As quality falls, watch smooth skies for banding and skin tones for block artifacts.
When PNG is the right call
PNG suits screenshots, UI mockups, charts, logos, and pixel art where edges and text matter. Flat-color regions compress efficiently, and alpha transparency makes it a familiar choice for logos placed on different backgrounds.
PNG can become large for photographs. If a photo needs transparency, export both PNG and WebP and compare size, appearance, and compatibility with the destination.
WebP: the sensible default for the web
For a photograph on the web, WebP is worth testing first. A smaller file takes less time to transfer, and the saving compounds on image-heavy pages. Check that the destination accepts the format and inspect the exported quality before committing.
The destination decides whether WebP is appropriate. It is a strong web candidate, but a document application or upload form may reject it. If support is unclear, prepare JPG or PNG; if requirements are published, follow them.
A decision table you can memorize
| The image is… | Best pick | Why |
|---|---|---|
| A photo for a website | Compare WebP first | Often produces a smaller file |
| A photo for email or documents | JPG | Broadly supported photo format |
| A screenshot or anything with text | PNG | Avoids lossy compression on text edges |
| A logo or image needing transparency | PNG or WebP | Both carry an alpha channel |
| A flattened file you'll keep editing | PNG | Lossless pixels; keep any layered source separately |
Converting without wrecking quality
Two rules cover most mistakes. First, move from lossless to lossy at the end rather than midway through editing. Second, converting in the other direction rescues nothing: saving an over-compressed JPG as PNG makes the file larger while preserving the compression artifacts.
Boltpic's converter processes the selected image in the current browser. Choose the target format, compare the result, and download a new file. Keep the original separately if you may need to convert again.