What this tool does
Local Image Converter changes the format and the size of pictures without sending them anywhere. It reads PNG, JPEG, WebP, GIF, BMP and SVG files, plus AVIF in current browsers, and saves them as PNG, JPEG, WebP or an ICO favicon. If your browser can also write AVIF, that option appears in the format list.
You can add many files at once. Each one is converted in turn, and changing a setting converts the whole batch again, so you can move the quality slider and watch the file sizes change before you download anything. Select a thumbnail to compare the original with the result under a slider.
Hitting a file size
Upload forms often refuse anything over a set size. For JPEG and WebP, switch "Compress by" to File size and type the limit in kilobytes. The tool lowers the quality until each file fits, stopping at 60 so the picture still looks good, and if that is not enough it makes the picture smaller as well. Each row shows the quality it settled on.
PNG, JPEG or WebP?
- JPEG is the safe choice for photos. Every device and app opens it. It has no transparency, so see-through areas are filled with the background colour you choose.
- PNG is lossless and keeps transparency. Use it for screenshots, logos, icons and anything with sharp edges or text. Photos saved as PNG are usually much larger than the same photo as JPEG.
- WebP usually gives a smaller file than JPEG at similar quality and keeps transparency. All current browsers show it, but some older apps and upload forms still refuse it.
Resizing
Scale by percent, set a width or a height in pixels, fit everything inside a maximum box, or pick a preset such as 1080 × 1080 for a square post, 1200 × 630 for a link preview or 64 × 64 for a favicon. Presets always produce the exact size: choose whether to crop the edges, add a background, or fit inside without cropping.
Large reductions are done in several steps, which keeps fine lines and text smooth instead of jagged.
Privacy
Your images never leave this device. The page has no upload step and no server that receives files: your browser opens each picture, redraws it and saves the result into memory, and the download comes straight from there. Once the page has loaded it keeps working with the network switched off.
Converting also removes hidden metadata. The saved files carry no EXIF data, which means no camera model, no capture time and no GPS location. Photos taken sideways are turned upright first, so they still look right without that data. Colour profiles are dropped as well, and the result is saved as standard sRGB.
Questions
Is there a limit on file size or number of files?
There is no set limit. Everything is held in your device's memory, so a phone will manage fewer large photos than a desktop computer. A result can be at most 16,384 pixels on a side; anything larger is scaled down to fit. A ZIP download can hold up to 4 GB.
Why did my file get bigger?
This usually happens when a photo is saved as PNG, or when a JPEG is saved again at a higher quality than it had. Try JPEG or WebP with quality around 80.
Can it convert HEIC photos from an iPhone?
Only in browsers that can open HEIC themselves, which today means Safari. In other browsers the file is listed with a message saying it could not be opened.
How do I make a favicon?
Add a square logo and choose ICO. You get one favicon.ico style file that holds 16, 32 and 48 pixel versions, which is what browsers and Windows shortcuts look for. For a single PNG icon, use the 64 × 64 or 512 × 512 preset with PNG instead.
Can I rename the files?
Yes. Type a pattern under File names, for example shop-{n} or {name}-{width}. If two files would end up with the same name, the later one gets a number added.
What happens to animated GIF or WebP files?
Only the first frame is converted. The result is a still image.
Does it remember my settings?
Yes. Your last format, quality and size settings are stored in this browser. Your images are not stored: they are gone when you close or reload the page.