Image Compressor
Reduce image file sizes and export as WebP or JPEG.
Select images
Choose one or multiple images to compress.
Compression settings
Choose the format, quality and maximum dimensions.
Compressed images
Compare file sizes and download the results.
An image compressor reduces download size through encoding settings, pixel resizing or both. Start with a copy of the original, test one representative image, inspect text and edges at normal display size, and then apply the chosen settings to similar files.
Upload a Copy and Choose Output Settings
The tool loads the image into the browser, optionally resizes it, and exports a new JPEG or WebP file using browser canvas processing.
Lower quality settings usually create smaller files but may also introduce visible compression artifacts. Reducing image dimensions can provide an additional file-size reduction.
How Image Compression Reduces Size
Suppose you have a 4000 × 3000 JPG photo for a blog post. You could select WebP output, set quality to around 0.80, and limit the width to 1200 px.
The resulting file will usually be much smaller than the original while retaining enough quality for typical web use.
Example: Prepare a Photo for the Web
JPEG does not support transparency, so transparent areas are replaced with the selected background color. Compression and canvas export may also remove metadata such as EXIF or GPS information.
Always preview the result and keep the original image when quality or metadata matters.
Match Format to Image Content
JPEG is widely compatible and effective for photographs but cannot store transparency. WebP is supported by modern browsers, can provide efficient compression, and supports alpha transparency. Select according to the destination and the visible result, not the format name alone.
Resize Before Chasing Lower Quality
Reducing pixel dimensions can save more bytes than changing quality alone. A camera image several thousand pixels wide is usually unnecessary in a modest content column. Choose dimensions that cover the largest real display size, including high-density screens when relevant, without sending far more pixels than the layout uses.
Keep the original aspect ratio unless deliberate cropping is required. Enlarging a small source creates additional pixels through interpolation but cannot restore detail that was never captured. Upscaling can make blur and compression artifacts more visible.
Inspect Artifacts and Color Changes
Lossy quality settings trade file size against visible fidelity. Lower values may create blocks, ringing near edges, softened texture, banding in gradients, or color smearing around text. The same number can behave differently across formats, browsers, and image subjects.
Test more than one setting on faces, fine texture, gradients, logos, and small high-contrast text. Inspect at the final display size and at 100% zoom. The correct result is the smallest file that still meets the destination’s visual requirements.
Transparency, EXIF and Privacy
For a blog photo, resize to the largest displayed width and test WebP or JPEG at a moderate quality. For a screenshot, reduce quality cautiously because text and interface edges reveal artifacts quickly.
Build a Repeatable Compression Workflow
PNG and WebP can store transparent pixels; JPEG cannot. When exporting a transparent source to JPEG, choose a background color that matches the destination. Otherwise a logo may display an unwanted rectangle. Inspect alpha edges on both light and dark backgrounds because antialiasing can reveal a fringe.
Metadata and Format Limitations
Compression does not guarantee a percentage saving, and aggressive settings can damage text, gradients, and fine detail. Transparent input requires WebP output or a deliberate JPEG background. Browser-canvas export may remove EXIF camera information, GPS coordinates, embedded thumbnails, color profiles, and other metadata. Keep the original whenever archival details, animation, vector structure, or professional color management matters.
Related Image Tools
Crop before compression with the Image Cropper, create a dedicated WebP with the WebP Converter, or use Image Converter Pro when PNG output is needed.
Privacy and Browser Performance
Processing runs locally in your browser, and selected files are not intentionally uploaded to AjaxCalculators for server-side conversion. Use a trusted device for sensitive images and protect files saved to the Downloads folder.
Large images can consume substantially more memory after decoding than their compressed file size suggests. If a batch stalls, process fewer files together, reduce dimensions, or close other tabs. Mobile devices and low-memory computers may reach browser limits sooner.
Website Publishing Workflow
Downloading a new file does not update WordPress, HTML, CSS, a CDN, or responsive image references automatically. Upload the result, update every intended reference, preserve descriptive alternative text, and confirm that the server returns the correct content type. Add width and height attributes where appropriate to reserve layout space.
Test the finished page on phone and desktop. File format is only one performance factor; rendered dimensions, responsive sources, caching, lazy loading, and whether the image is initially visible also matter.
Quality-Control Checklist
- Open the downloaded file independently.
- Confirm dimensions, orientation, and aspect ratio.
- Compare file size and visible quality.
- Verify transparency or background color.
- Inspect text, faces, gradients, and sharp edges.
- Keep the source until publishing is confirmed.
Plan the Output Before Processing
Define where the new image will appear, its maximum rendered dimensions, whether transparency is required, and which browsers or applications must open it. A file for a product grid has different priorities from an archival master, printable graphic, email attachment, or social card. Starting with the destination prevents unnecessary resizing and repeated lossy exports.
When compression is the goal, measure both byte reduction and perceived quality. Compress a representative test image before processing an entire collection, then use consistent settings only for assets with similar content, dimensions, and purpose each time.
Compare Results Consistently
Use the same crop and pixel dimensions when comparing formats or quality settings. Record the resulting file size and inspect the image on the intended background. A tiny saving is not worthwhile if it damages a logo, face, gradient, or small text. Conversely, sending a much larger file does not improve an image beyond the detail users can actually see.
Keep one untouched master and create named derivatives for publishing. Include useful subject or size information in filenames without exposing private data. After replacement, check caching, broken URLs, captions, attribution, structured data, and any page that reuses the asset.
Dimensions often matter more than a tiny quality change
A 4000-pixel photograph displayed at 800 pixels transfers far more data than the layout needs. Creating an appropriately sized derivative can reduce weight while preserving clearer detail than extreme quality reduction at the original dimensions.
Use objective and visual checks together
Compare bytes, dimensions and format, but also inspect faces, gradients, fine text and hard edges. The MDN format guide explains when lossy or lossless output is appropriate.
Frequently Asked Questions
What formats can I compress?
Upload PNG, JPG, WebP, or SVG. The tool exports a new JPEG or WebP file.
What quality should I choose?
Start moderately, compare preview and file size, and lower quality only until further savings harm appearance.
Will resizing reduce size?
Usually. Fewer pixels generally require fewer bytes, provided the dimensions still suit the display.
What happens to transparency in JPEG?
Transparent pixels are replaced with the chosen background because JPEG has no alpha channel.
Does compression remove EXIF or GPS?
Canvas export may remove EXIF, GPS, embedded profiles, and other metadata.
Are images uploaded?
No. Compression runs locally, and selected files are not intentionally uploaded to AjaxCalculators.
