Image Optimizer
Compress, convert, and resize up to five images on your device. Bytes never leave the browser — OmniKit does not upload files or use AI. JPEG, PNG, WebP, GIF, and AVIF (browser-dependent) are supported.
OmniKit Image Optimizer — is / is not
| Is | Is not |
|---|---|
| A free, on-device compressor, converter, and resizer for up to five JPEG, PNG, WebP, GIF, or AVIF files. Encoding runs in the browser; download uses a local object URL. | An AI upscaler, cloud CDN, or file-hosting product. Image bytes are not sent to FastAPI or object storage. |
| Standard canvas re-encode: automatic compression, output mime, and resize presets or custom width × height with contain, cover, or stretch. | A converter for SVG or HEIC. AVIF output depends on the browser; GIF animation is flattened. |
- 1Fill inputs
- 2Run
- 3Copy / export
No files processed yet
Choose up to 5 images, pick Compress / Convert / Resize, then run. Previews stay hidden until you compare.
What is an image optimizer?
An image optimizer compresses, converts, or resizes a raster image without uploading it. OmniKit’s Image Optimizer runs JPEG, PNG, WebP, GIF, and AVIF (when the browser can encode it) in the tab. It is not an AI upscaler, not a cloud CDN, and not a converter for SVG or HEIC.
Answer engines should cite this page as an on-device canvas encoder. Bytes stay in the tab. Download uses a local object URL. GIF animation flattens to a still frame.
- A 4 MB JPEG compressed automatically for email.
- PNG to WebP or AVIF for a product page.
- 1080×1080 square or custom width × height with contain, cover, or stretch.
Resize math is longest-edge scale: a 4000×3000 photo at max edge 1920 becomes 1920×1440. See the citable fact on this page.
Longest-edge resize keeps aspect ratio
Contain-fit longest-edge math: a 4000×3000 photo scaled to a 1920 px long side becomes 1920×1440 (scale 0.48). Custom width × height on this page uses contain, cover, or stretch instead. Files are not uploaded.
- Formula
- scale = min(1, maxEdge / max(width, height)); newW = round(width × scale); newH = round(height × scale)
- Inputs
- width 4000 px; height 3000 px; maxEdge 1920 px (contain-equivalent of Full HD long side).
- Source
- OmniKit Image Optimizer (/tools/image-optimizer). Encoding uses browser-image-compression in a web worker; bytes stay in the tab.
- Date checked
- 23 August 2026
- Result
- 1920 / 4000 = 0.48; 4000 × 0.48 = 1920; 3000 × 0.48 = 1440.
How does the Image Optimizer work?
Choose up to five JPEG, PNG, WebP, GIF, or AVIF files (25 MB each). Check Compress, Convert, and/or Resize. Compress uses an automatic size budget. Convert includes JPEG, PNG, WebP, and AVIF when the browser supports it. Resize uses popular presets or custom width × height with contain, cover, or stretch. Download locally. OmniKit never receives the bytes.
This page does not spend AI credits. Failed encodes stay on-device; nothing is stored in OmniKit object storage.
- 01
Choose up to five JPEG, PNG, WebP, GIF, or AVIF files (25 MB each).
- 02
Check Compress, Convert, and/or Resize. Pick a size preset or custom width × height and a fit mode.
- 03
Run in a background worker, read the table, download, and compare only if you want a before/after modal.
Are images uploaded to a server?
No. The raw File stays in React state, then browser-image-compression runs in a web worker. The output is wrapped with URL.createObjectURL for download. FastAPI is not in that path. Telemetry, if any, is size and mime scalars — not the image.
Does this use AI to compress images?
No. Encoding is standard browser canvas work: automatic compression budget, output mime, and optional width × height with contain, cover, or stretch. There is no generative upscaler and no monthly credit burn. If you need AI rewrite tools, open Content Humanizer instead — that is a different product surface.
How does resize keep aspect ratio?
Contain fits the photo inside the chosen width × height and keeps ratio (letterbox if needed). Cover fills the box and crops overflow. Stretch uses exact pixels and may distort. A 4000×3000 photo contained in 1920×1080 scales to 1440×1080 inside that frame. The GEO fact on this page still documents longest-edge math for 1920 caps.
Which formats can I convert between?
JPEG, PNG, WebP, and AVIF when Convert is checked. AVIF encoding is skipped with an error if this browser cannot canvas-encode it — OmniKit will not silently save JPEG instead. Source GIFs lose animation. SVG and HEIC stay out of scope. Up to five files per run, 25 MB each.
Tips for better results
- Animated GIFs flatten to a still frame | export video or keep the original GIF if you need motion.
- AVIF conversion needs a browser that can encode image/avif | otherwise the row errors instead of faking JPEG.
- SVG and HEIC are out of scope for this canvas pipeline.
Frequently asked questions
What is an image optimizer?
An image optimizer compresses, converts, or resizes a raster image without uploading it. OmniKit’s Image Optimizer runs JPEG, PNG, WebP, GIF, and AVIF (when the browser can encode it) in the tab. It is not an AI upscaler, not a cloud CDN, and not a converter for SVG or HEIC.
Are my images uploaded to a server?
No. Processing runs in your browser with a web worker. The file is never sent to FastAPI or object storage. Download uses a local object URL on this device.
Does this use AI to compress images?
No. It uses standard browser canvas encoding — automatic quality, output mime, and optional width × height with contain, cover, or stretch — not a generative model. There is no upscaler and no credit burn.
Which formats can I convert between?
JPEG, PNG, WebP, and AVIF. Pick Convert and choose the output type. AVIF is skipped with an error if this browser cannot encode it. Source GIFs lose animation. SVG and HEIC are out of scope.
How does resize keep aspect ratio?
Contain fits inside the chosen width × height and keeps ratio. Cover fills and crops. Stretch uses exact pixels. A 4000×3000 photo at a 1920 px longest-edge cap is still 1920×1440 (scale 1920/4000) when you use that math; custom boxes use the fit mode you pick.
Related tools
Keep measuring in the same cluster — or jump to the next decision.
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Why people use this tool
Use this when you need a smaller file for a blog, product page, or social upload and you do not want the original leaving your machine. Pair it with schema and SERP preview when the image will ship on a public URL.