Images are the largest files on most websites. Unoptimized images slow down your site, hurt SEO, and increase bandwidth costs. These 10 free tools help you compress, convert, and optimize images without losing quality.
1. TinyPNG – Best for Bulk Compression
URL: https://www.baike300.com/article/176.html
TinyPNG is the most popular free image compression tool. It uses smart lossy compression to reduce PNG and JPEG file sizes by 50-80% while preserving visual quality. You can upload up to 20 images at once (5 MB each). The compressed images are delivered instantly. There's also a WordPress plugin for automatic compression on upload.
2. Squoosh – Google’s All‑in‑One Tool
URL: https://squoosh.app
Squoosh is a free, open‑source image optimization tool built by Google. It supports multiple formats including WebP, AVIF, JPEG XL, and traditional JPEG/PNG. You can adjust quality, color palette, and compression settings with real‑time preview. All processing happens in your browser — nothing is uploaded to any server.
3. ImageOptim – Best for Mac Users
URL: https://imageoptim.com
ImageOptim is a free desktop app for macOS that compresses images without uploading them to the cloud. It removes metadata, optimizes color palettes, and applies compression. Drag and drop images, and the app does the rest. Great for designers who handle sensitive or private images.
4. Compressor.io – Simple and Fast
URL: https://compressor.io
Compressor.io is a fast online image compressor that supports JPEG, PNG, GIF, and SVG. It offers both lossy and lossless compression options. The free tier has a 10 MB file size limit. The interface is clean and beginner‑friendly — upload, compress, download.
5. Kraken.io – Advanced Image Optimizer
URL: https://kraken.io
Kraken.io is a powerful image optimizer with both web and API versions. The free tier allows up to 1 MB files and 10 images per batch. It supports JPEG, PNG, SVG, and GIF formats. The platform offers lossy, lossless, and expert compression modes, as well as WebP conversion and image resizing.
6. ShortPixel – WordPress Plugin and Web Tool
URL: https://shortpixel.com
ShortPixel offers a free online image compression tool and a WordPress plugin. The free tier allows 100 credits per month (one credit = one image). It supports JPEG, PNG, GIF, and WebP formats, and automatically converts images to WebP for browsers that support it. Great for WordPress site owners.
7. Optimizilla – Perfect for JPEG/PNG
URL: https://imagecompressor.com
Optimizilla is a minimalist online image compressor optimized for JPEG and PNG files. It compresses up to 20 images at once with adjustable quality sliders. You can preview each image side‑by‑side before downloading. The interface is simple and ad‑free.
8. CloudConvert – Format Converter
URL: https://cloudconvert.com
CloudConvert is a powerful online file converter that supports image format conversion (PNG to WebP, JPEG to WebP, PNG to SVG, etc.). The free tier includes 25 conversions per day. It also offers basic compression and resizing options. Good for batch format conversion and automation.
9. PNGQuant – PNG‑Specific Compression
URL: https://pngquant.org
PNGQuant is an open‑source tool that compresses PNG files by reducing the number of colors in the image. It can reduce PNG file sizes by 50-70% while preserving transparency. You can use the web version (pngquant.com) or install it via command line for batch processing on your VPS.
10. Raster – Convert Images to WebP and AVIF
URL: https://raster.app
Raster is a free online tool that converts JPEG and PNG images to modern formats like WebP and AVIF. It supports bulk conversion (up to 100 images at once) and offers quality and size controls. All processing happens in your browser — no uploads to external servers.
More resources: Check our technical tutorials or VPS reviews.