Why Image Formats Matter More Than You Think
Choosing the wrong image format can double your page load time, ruin a transparent logo, or produce visible artifacts on a client’s product photo. The three most widely used formats on the web today are PNG, JPG (also called JPEG), and WEBP. Each one was designed to solve a different problem, and understanding their strengths and weaknesses will help you make better decisions every time you save, export, or convert an image.
This guide breaks down the technical details in plain language, compares the formats side by side, and provides clear recommendations for every common use case. If you need to convert between any of these formats, ConvertKr’s Image Converter handles it instantly in your browser.
JPG: The Workhorse for Photographs
How JPG Compression Works
JPG uses lossy compression, which means it permanently discards some image data to achieve smaller file sizes. The algorithm analyzes blocks of pixels and removes subtle color variations that the human eye is unlikely to notice. At high quality settings (85-95%), the visual difference from the original is nearly imperceptible. At lower settings (40-60%), file sizes shrink dramatically but compression artifacts — blocky patches and color banding — become visible, especially around sharp edges and text.
When to Use JPG
- Photographs and realistic images: JPG excels at compressing the smooth gradients and complex color palettes found in photos. A 5000×3000 pixel photo might be 15 MB as a raw file but only 2 MB as a high-quality JPG.
- Email attachments and social media: When you need to keep file sizes small for sharing, JPG is the most universally supported option.
- Print-ready images: Most print workflows accept JPG at high quality settings without issues.
When to Avoid JPG
JPG does not support transparency. If your image has a transparent background — a logo, icon, or cutout — JPG will fill that area with a solid color, usually white. JPG also performs poorly on images with sharp lines, flat colors, and text. Screenshots, diagrams, and vector-style graphics will show noticeable artifacts around edges. Finally, every time you re-save a JPG, it recompresses and loses more quality. Avoid repeatedly editing and saving the same JPG file.
PNG: Lossless Quality and Transparency
How PNG Compression Works
PNG uses lossless compression. Every single pixel is preserved exactly as it was in the original. The compression algorithm finds patterns and redundancies in the pixel data to reduce file size without removing any information. This means you can open, edit, and re-save a PNG a thousand times without any quality degradation.
The Transparency Advantage
PNG supports full alpha-channel transparency. Each pixel can be fully opaque, fully transparent, or anywhere in between. This is essential for logos, icons, UI elements, and any graphic that needs to sit on top of different backgrounds without a visible bounding box. If you need to remove the background from a product photo or portrait, ConvertKr’s Background Remover can do that, and PNG is the format that will preserve the result.
When to Use PNG
- Logos and icons: Sharp edges, flat colors, and transparency make PNG the only sensible choice.
- Screenshots and diagrams: Text and UI elements remain crisp because no data is discarded.
- Graphics requiring editing: Since PNG is lossless, it’s safe as a working format through multiple rounds of edits.
- Images with transparency: Any time you need a transparent or semi-transparent background.
When to Avoid PNG
PNG files are significantly larger than JPG for photographs. A photo saved as PNG might be 10 to 20 MB, while the same image as a high-quality JPG would be 2 to 3 MB. For websites that load many photos, PNG will slow everything down. Use PNG for graphics and JPG for photos, or better yet, consider WEBP for both.
WEBP: The Modern All-Rounder
How WEBP Compression Works
Developed by Google and released in 2010, WEBP supports both lossy and lossless compression, transparency, and even animation. In lossy mode, WEBP typically produces files 25-35% smaller than JPG at equivalent visual quality. In lossless mode, WEBP files are about 25% smaller than PNG. This makes WEBP the most efficient format for web delivery in almost every scenario.
Browser Support in 2026
As of 2026, WEBP is supported by every major browser: Chrome, Firefox, Safari, Edge, and Opera. Safari added full support in version 14 (2020), which was the last holdout. For websites targeting modern browsers, there is no compatibility barrier to using WEBP. However, some older desktop applications, email clients, and print workflows may not recognize the format, so you may still need JPG or PNG for those contexts.
When to Use WEBP
- Website images: WEBP delivers the best combination of quality and file size for web use. If page speed matters to you — and it should — WEBP is the default choice.
- Images needing transparency on the web: WEBP supports alpha transparency with smaller file sizes than PNG.
- Replacing both JPG and PNG on websites: A single format that handles photos and graphics efficiently simplifies your workflow.
When to Avoid WEBP
If your images will be used in print, in email newsletters rendered by older clients, or in desktop software that doesn’t support WEBP, you’ll need to convert to JPG or PNG. ConvertKr’s Image Converter can handle that conversion in either direction.
Side-by-Side Comparison
Here is how the three formats stack up across the most important criteria:
- Compression type: JPG is lossy only. PNG is lossless only. WEBP supports both lossy and lossless.
- Transparency: JPG has no support. PNG has full alpha-channel support. WEBP has full alpha-channel support.
- Animation: JPG has no support. PNG has no native support (APNG exists but is niche). WEBP supports animation.
- File size for photos: JPG is small. PNG is very large. WEBP is smallest.
- File size for graphics: JPG is small but shows artifacts. PNG is moderate. WEBP is smallest.
- Quality after re-saving: JPG degrades each time. PNG stays identical. WEBP stays identical in lossless mode, degrades in lossy.
- Browser support: All three have universal support in 2026.
- Print compatibility: JPG is excellent. PNG is excellent. WEBP is limited.
Practical Recommendations by Use Case
For Websites and Blogs
Use WEBP as your primary format. Convert existing JPG and PNG assets using the Image Converter, and compress them further with the Image Compressor if needed. Your pages will load faster and your visitors will have a better experience.
For Social Media
Most social platforms accept JPG and PNG. Some accept WEBP. For maximum compatibility, export photos as JPG at 85% quality and graphics with transparency as PNG. If you need to resize or crop before uploading, the Image Cropper can prepare your images to the exact dimensions each platform requires.
For Email
Stick with JPG for photos and PNG for logos. Email clients have inconsistent WEBP support, and a broken image in an email is worse than a slightly larger file.
For Archiving and Editing
Keep your master files in PNG (or the original raw format if you’re working with camera files). PNG’s lossless nature means you’ll never lose quality during your editing workflow. Export to JPG or WEBP only when you’re ready to distribute the final version.
Converting Between Formats
No matter which format you start with, there are times when you need to convert. A client sends a PNG photo that should be a JPG. A web developer needs WEBP versions of all your assets. A printer rejects your WEBP file and asks for JPG. ConvertKr’s Image Converter handles all of these conversions instantly, with no file uploads and no quality loss beyond what the target format requires. Open the tool, drop your files, choose the output format, and download the results.