RasterMint

Image Format Guide

PNG vs JPG: Which image format should you use?

PNG and JPG (also called JPEG) are the two most common image formats on the web. They serve different purposes, and choosing the wrong one can result in blurry text, unnecessarily large files, or lost image quality. This guide explains the key differences and when to use each format.

Quick comparison

FeaturePNGJPG
CompressionLosslessLossy
TransparencyYes (alpha channel)No
Text claritySharpArtifacts around text
File sizeLargerSmaller
Best for photosAcceptableIdeal
Best for text/screenshotsIdealPoor
Color depthUp to 48-bit24-bit
AnimationNo (APNG is separate)No

What is PNG?

PNG (Portable Network Graphics) is a lossless image format. When you save an image as PNG, no data is discarded. Every pixel is preserved exactly as it was. This makes PNG the preferred format for images with text, line art, logos, screenshots, and any content where sharp edges matter.

PNG also supports an alpha channel for transparency. This means parts of the image can be fully or partially transparent, which is essential for logos, icons, and layered graphics used on websites and in presentations.

The trade-off is file size. Because PNG preserves all data, files tend to be larger than JPG equivalents. A high-resolution PNG can be several megabytes, while the same image as a JPG might be a few hundred kilobytes.

What is JPG?

JPG (Joint Photographic Experts Group) is a lossy image format designed for photographs. It achieves much smaller file sizes by discarding some image data that the human eye is less likely to notice. This compression works well for natural photographs with smooth color gradients.

JPG does not support transparency. Every pixel in a JPG image is fully opaque. It also does not handle text or sharp edges well — you will often see visible compression artifacts around text, logos, and high-contrast boundaries.

Each time you edit and re-save a JPG, more data is lost. This is called generational loss and can result in progressively lower image quality over multiple edits.

When to use PNG

  • Screenshots and screen captures where text must remain sharp
  • Document pages converted from PDF (text, forms, invoices, charts)
  • Logos, icons, and graphics with transparency
  • Images with text overlays for social media or presentations
  • Technical diagrams, floor plans, and engineering drawings
  • Any image that will be edited and re-saved multiple times

When to use JPG

  • Photographs for websites, blogs, and social media posts
  • Email attachments where file size matters more than pixel-perfect quality
  • Background images and hero banners on web pages
  • Any situation where smaller file size is a priority and minor quality loss is acceptable

PNG vs JPG for PDF conversion

When converting PDF pages to images, PNG is almost always the better choice. PDF pages typically contain text, lines, and vector graphics that need to stay sharp. JPG compression introduces visible artifacts around text characters and straight lines, making the converted page look blurry or pixelated.

The only exception is when the PDF consists entirely of photographs (like a photo book) and file size is the primary concern. Even then, PNG at 150 DPI often produces acceptable file sizes while maintaining quality.

RasterMint converts PDF pages to PNG by default, preserving text clarity and fine details at your chosen DPI setting (72, 150, or 300 DPI).

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