About Online Image Format Converter

The Glutool Image Converter lets you convert images between JPG, PNG, WEBP, BMP, and GIF formats in bulk. Whether you need to convert PNG screenshots to JPEG for smaller file sizes, transform images to WEBP for modern web performance, or ensure backward compatibility with older applications, this tool handles it all directly in your browser — fast, free, and with complete privacy.

Understanding Image Formats

Each image format has strengths and trade-offs. JPEG is ideal for photographs with millions of colors but does not support transparency. PNG preserves transparency and is lossless, making it perfect for logos, icons, and screenshots. WEBP combines the best of both worlds with superior compression for both lossy and lossless images. BMP is an uncompressed format used in legacy Windows applications. GIF supports animation but is limited to 256 colors. Choosing the right format depends on your use case, and this tool makes switching between them effortless.

Key Features

• Bulk conversion — convert dozens of images at once, saving hours on repetitive format changes for large asset libraries.
• Five format options — supports JPG, PNG, WEBP, BMP, and GIF as both input and output formats with full cross-conversion.
• Quality control — fine-tune output quality for lossy formats (JPEG, WEBP) to balance file size and visual fidelity.
• Live preview — see thumbnails of original and converted images side by side before downloading.
• Individual file control — download or remove each converted image independently from the batch.
• Client-side processing — images are converted in your browser. Nothing is uploaded to any server.

Step-by-Step Guide

1. Upload images — click the upload button or drag and drop one or more images into the drop zone. All common formats are accepted.
2. Select target format — choose your desired output format (JPG, PNG, WEBP, BMP, or GIF) from the format dropdown.
3. Adjust quality — for JPEG and WEBP, use the quality slider to set the compression level. Higher values mean better quality but larger files.
4. Convert — click Convert to process all images. Each file is converted independently and shown in the results list.
5. Download — download individual converted images or remove any you don't need from the results.

Format Comparison Guide

• JPG → PNG — useful when you need lossless quality or transparency. File size will increase but no further quality loss occurs.
• PNG → JPG — dramatically reduces file size for photographs. Transparency is replaced with a white background.
• Any → WEBP — the best option for web images. WEBP achieves 25-35% smaller files than JPEG and PNG at equivalent quality.
• WEBP → PNG/JPG — ensures compatibility with older browsers, email clients, or software that doesn't support WEBP.
• BMP → Any — converts uncompressed BMP files to modern, compressed formats for practical use and sharing.

Real-World Use Cases

• Converting PNG screenshots to JPEG or WEBP for smaller email attachments and faster uploads.
• Batch converting an entire image library to WEBP for website performance optimization.
• Converting WEBP images back to PNG or JPEG for compatibility with Word documents, PowerPoint, or older CMS platforms.
• Transforming BMP files from legacy systems into modern formats for web or mobile applications.
• Preparing images for specific platform requirements (e.g., some print services require JPEG or TIFF).