Image Compression Tool (JPG/PNG/WebP/AVIF/HEIC Batch Compression)

Image Compression Tool: Reduce Image Size Locally in the Browser

The goal of image compression is to reduce file size while keeping visual differences barely noticeable. This tool performs all processing locally in the browser: drop in images, choose a compression preset or set parameters manually, and start compression. You can then compare the file sizes and savings before and after compression and download individual files or package them into a ZIP. There is no upload interface, so images never leave your device.

Supported Input and Output Formats

Input supports JPG, PNG, WebP, AVIF, the common HEIC / HEIF formats used by phones, as well as GIF and BMP. Output can be set to Auto (recommended) or manually selected as JPG, PNG, WebP, or AVIF. In Auto mode, the tool tries to preserve the original format: GIF and BMP are output as PNG, while HEIC is output as JPG for broad compatibility. When outputting JPG, transparent areas are automatically filled with white. PNG and WebP preserve the transparency channel.

Four One-Click Compression Presets

• Original optimization: preserve the original format and dimensions with quality 90, suitable when you only want to reduce file size slightly.
• Web use: maximum side 1920 pixels, WebP, quality 80, suitable for websites and blog images.
• WeChat / social: maximum side 1280 pixels, JPG, quality 75, providing broad compatibility.
• Email attachment: maximum side 1280 pixels, JPG, quality 65, for smaller attachment sizes.

After selecting a preset, you can still manually change quality, output format, and maximum dimensions. Any manual adjustment switches the mode to Custom, making the current parameters clear at all times.

How Are HEIC Photos Handled?

iPhone devices use HEIC / HEIF by default, and many tools simply reject this format. This tool loads a HEIC decoder locally in the browser when needed, decodes the photo into pixels, and then compresses it. You do not need to convert HEIC to JPG first, and the decoding process does not upload the image over the network. When HEIC is detected, the output format automatically switches to Auto and produces JPG, although you can change it manually. If the current browser environment cannot decode HEIC, the tool displays a clear message instead of failing silently.

Quality, Dimensions, and PNG Quantization

The quality slider controls compression strength for JPG, WebP, and AVIF. Lower values produce smaller files, and 70 to 85 is generally a reasonable balance between size and image quality. Maximum width and height limit the output dimensions. When Keep aspect ratio is enabled, the image is reduced proportionally without distortion. PNG is lossless, so re-encoding alone often produces little size reduction. For PNG output, you can quantize colors to 256, 128, 64, or 32 colors, with the page indicating the corresponding image-quality impact. This is useful for icons, flat illustrations, and screenshots.

Batch Processing and Downloads

Up to 100 images can be processed at once. Additional files are reported and ignored. Compression runs sequentially to control memory usage, with a progress bar showing the current progress and an option to cancel. Each file displays its own status, such as processing, loading the HEIC decoder, completed, failed, no compression needed, or file size increased. After processing, a single image is shown with a side-by-side before-and-after comparison and compression ratio. Multiple images switch to a table showing filename, original size, compressed size, savings ratio, and download buttons. Individual downloads and Download All (ZIP) are supported.

Handling Exceptional Cases

Compression results depend on the image itself. Images that have already been compressed, very small images, and images with rich detail may have limited room for further reduction. The page suggests lowering quality, limiting dimensions, or switching to WebP or AVIF. If the compressed file is larger than the original, the tool keeps the original by default and provides a separate option to download the compressed version anyway. ZIP downloads also use the original file for such cases, so you do not end up with a larger file. Images exceeding 25 megapixels receive a warning that processing may be slower. Files larger than 40 MB, unsupported file types, and invalid images produce clear errors.

Use Cases

• Website and blog images: resize to 1920 pixels and output WebP to improve page loading speed.
• Social media publishing: keep images within 1280 pixels to reduce the impact of secondary platform compression.
• Email attachments: reduce the size of multiple photos for easier sending.
• Asset organization: batch-compress screenshots and design files to save local and cloud storage space.

Privacy and Data Security

Decoding, resizing, and encoding are all performed locally in the browser. There is no upload interface, images are not sent to a server or saved, and they are released from memory after the page is refreshed or closed. If the browser does not support AVIF export, such as certain Firefox or Safari versions, the AVIF option is automatically disabled and the page explains why. JPG or WebP can be used instead.