Image Optimizer
Free image optimizer — compress, resize, and convert JPG, PNG, and WEBP images in one step. Preview before/after and download. Browser-only, no server upload.
The Image Optimizer combines image compression, format conversion, and resizing into a single browser-based tool — replacing the need to use separate tools for each step. Upload any JPG, PNG, WEBP, GIF, or BMP image and configure all three transformations at once: change the output format, adjust the quality level, and set maximum dimensions. The result is immediately previewed alongside the original so you can compare before downloading.
Choose your output format from JPG, PNG, or WEBP. JPG and WEBP support a quality slider from 10% to 100% — higher quality means larger file size. PNG is lossless and produces the sharpest result at the cost of larger files, making it ideal for logos, icons, and screenshots with flat colors or text. WEBP typically achieves the best compression-to-quality ratio for photographs and is the recommended format for modern websites.
The resize controls let you set a maximum width and height. With "Shrink only" mode (the default), the tool only scales the image down — images smaller than your limits are left at their original size. With "Exact dimensions" mode, the image is forced to exactly the dimensions you specify regardless of the original size. Both modes preserve the aspect ratio unless you choose exact dimensions.
The before/after preview shows the original file size and pixel dimensions alongside the optimized result, with a savings badge showing how many kilobytes were saved and the percentage reduction. If the output is larger than the input (which can happen when converting PNG to JPG at high quality), the badge highlights this in amber so you can adjust settings.
Common use cases include optimizing product photos for an e-commerce store, reducing image sizes before uploading to a CMS, converting screenshots for web use, and batch-preparing images for a portfolio or marketing campaign.
Frequently Asked Questions
- What is the difference between JPG, PNG, and WEBP?
JPG uses lossy compression and is best for photographs where small quality reductions are imperceptible. PNG is lossless and best for logos, icons, and images with text or flat colors where sharpness matters more than file size. WEBP is a modern format that achieves better compression than both JPG and PNG at equivalent quality and is supported by all modern browsers — it is the best choice for web images in most cases.
- What quality setting should I use?
For web images, 75-85% quality for JPG and WEBP is usually indistinguishable from 100% quality to the human eye while reducing file size by 50-70%. For thumbnails and previews, 60-70% is often acceptable. For print or archival use, use 90-100%. PNG ignores the quality setting as it is always lossless.
- Does my image get uploaded to a server?
No. All processing happens entirely in your browser using the HTML Canvas API. Your image is read locally into memory, processed client-side, and the result is downloaded directly from your browser. Nothing is transmitted to any external server.
- What is the difference between Shrink only and Exact dimensions mode?
Shrink only mode (the default) only scales the image down if it exceeds your maximum width or height. Images smaller than your limits are left at their original size. Exact dimensions mode forces the image to exactly the width and height you specify, which may upscale small images and will crop or stretch the aspect ratio if width and height have a different ratio than the original.
- Why is my output file larger than the input?
This can happen when converting from a heavily compressed format to a less compressed one — for example, converting a very compressed JPG to PNG, or increasing quality above the original compression level. The amber savings badge will indicate when the output is larger. Try lowering the quality slider or switching to WEBP format for better compression.
← Back to all free tools