Image Format Converter

Convert images between JPEG, PNG, WebP, and BMP. Batch convert multiple files with quality control and size comparison.

What is Image Format Converter?

An Image Format Converter transforms image files from one format to another, allowing you to optimize images for specific use cases—web performance, print quality, transparency support, or maximum compatibility. Image format choice has a significant impact on web performance, visual quality, and browser compatibility. JPEG (Joint Photographic Experts Group) is the most universally supported format, ideal for photographs with gradients and complex colors, but it does not support transparency and introduces compression artifacts at lower quality settings. PNG (Portable Network Graphics) is lossless—it preserves every pixel exactly—making it perfect for screenshots, logos, icons, and images with text, and it supports full alpha channel transparency. WebP, developed by Google, offers superior compression compared to both JPEG and PNG: WebP images are typically 25–35% smaller than equivalent JPEG files and 25–50% smaller than PNG files at comparable visual quality, while also supporting transparency. Converting your website's images from JPEG or PNG to WebP is one of the highest-impact optimizations for improving Google PageSpeed scores and Core Web Vitals. BMP is an uncompressed format used in some legacy systems and Windows applications. This tool performs all conversions directly in your browser with no server uploads.

How to Use Image Format Converter

Click the upload area or drag and drop one or more image files to upload them—the tool supports batch conversion of multiple files simultaneously. For each uploaded image, the tool displays a preview, the original format, dimensions, and file size. Select the target output format from the dropdown: JPEG (best for photographs), PNG (lossless, supports transparency), WebP (best for web performance), or BMP (legacy compatibility). For JPEG and WebP outputs, use the quality slider to balance file size against visual quality—80–85% is recommended for most web uses. A before/after size comparison shows exactly how much the conversion reduces or changes the file size. Click 'Convert All' to process all uploaded images at once, then download each converted file individually with its download button, or click 'Download All' to get a ZIP archive containing all converted files.

FAQ

Which image format is best for websites?

WebP is the modern best choice for web images—it achieves 25–50% smaller file sizes than JPEG and PNG at equivalent quality, supports transparency like PNG, and is supported by all modern browsers (Chrome, Firefox, Safari 14+, Edge). Use JPEG as a fallback for older browsers or when maximum compatibility is required. Use PNG when you need pixel-perfect lossless quality or full transparency support. Use SVG for logos, icons, and illustrations that need to scale to any size without pixelation.

Will converting JPEG to PNG improve the image quality?

No. Converting from a lossy format (JPEG) to a lossless format (PNG) does not recover any quality lost during the original JPEG compression—it only preserves the current state of the image without further degradation. The resulting PNG file will be much larger than the original JPEG but will not look any better. The only time this conversion makes sense is when you need to edit the image further and want to avoid additional lossy compression cycles during re-saving.

Can I convert PNG with transparency to JPEG?

Yes, but JPEG does not support transparency—the transparent areas will be filled with a background color (typically white). If your PNG has a transparent background that you want to preserve, convert to WebP (which supports transparency) instead of JPEG. If you do need JPEG output with a specific background color, you can set the fill color before converting.

Can I batch convert an entire folder of images?

Yes. Select all the images you want to convert (Ctrl+A in the file picker or drag multiple files), and the tool processes them all simultaneously in your browser. All conversions happen in parallel using the Canvas API, so even large batches complete quickly. Download individual converted files or use 'Download All' for a ZIP archive of all results.

Why is my WebP file larger than the original JPEG?

This can happen when the source JPEG was already heavily compressed at a very low quality (below 60%). WebP's compression algorithm works best on high-quality source images. If the input is a highly compressed JPEG, WebP may not be able to reduce the file size further. Try adjusting the quality slider—for already-compressed JPEGs, a lower WebP quality setting (70–75%) may produce a smaller output than trying to match the original quality exactly.