Overview
Resize images to any pixel dimension
Image resizing changes the pixel dimensions of an image, making it larger or smaller. Most resizing in practice is downscaling: a 12-megapixel phone photo is far bigger than what you need for a profile picture, a forum avatar, or an inline blog image. Downscaling keeps the visual content but produces smaller files that load faster and meet upload requirements. The ToolHub resizer lets you set exact pixel dimensions, scale by percentage, and lock the aspect ratio so your images do not get stretched.
All resizing is done with high quality canvas smoothing in your browser. Images never leave your device.
Step-by-step
How to resize an image
- 1
Drop in your image
Drag a JPG, PNG, or WebP file into the upload area. The resizer reads the original dimensions and shows them above the controls. - 2
Set width or height
Type the dimension you want in pixels. With the lock icon enabled, the other dimension updates automatically to preserve the aspect ratio. Disable the lock to set width and height independently. - 3
Or use a percentage preset
Click 25%, 50%, or 75% to scale the image by that percentage of the original dimensions. This is the fastest way to make an image roughly half size or quarter size. - 4
Resize and download
Click resize. The output is shown with a preview and the new file size. Download with one click.
Reference
Common image sizes you might need
- Profile pictures: 400 by 400 pixels (most platforms)
- WhatsApp DP: 500 by 500 pixels
- YouTube thumbnail: 1280 by 720 pixels
- Instagram post: 1080 by 1080 pixels (square) or 1080 by 1350 (portrait)
- Facebook cover: 820 by 312 pixels
- Twitter / X header: 1500 by 500 pixels
- LinkedIn cover: 1584 by 396 pixels
- Blog inline image: 1200 by 630 pixels for good Open Graph preview
- Email signature: 300 to 400 pixels wide for retina display
Background
Aspect ratio explained
Aspect ratio is the relationship between an image width and its height, written as width to height. A 1920 by 1080 image has a 16:9 aspect ratio, the same as most TVs and YouTube videos. A 1080 by 1080 image has a 1:1 aspect ratio (square), used for Instagram posts. A 1080 by 1920 image has a 9:16 aspect ratio (vertical), used for stories and shorts.
Why locking the ratio matters
When you resize without locking the aspect ratio, you can change width and height independently. This stretches or squashes the image in one direction, distorting faces, logos, and proportions. Locking the ratio means changing one dimension automatically updates the other to keep proportions correct. Use unlocked mode only when you have a specific design reason to distort the image.
Use cases
When to resize
Social media profile pictures
Most platforms enforce a square 400 by 400 or 500 by 500 minimum. Resize and crop your photo to fit perfectly.
Forum and Discord avatars
Old forums often cap avatars at 100x100 or 128x128. Native phone photos are way too big until resized.
Email signatures
Logo files in email signatures should be 100 to 300 pixels wide so they load fast and do not break the layout.
Website thumbnails
Card thumbnails on a blog or shop are usually 400 to 600 pixels wide. Resizing keeps them crisp without wasting bandwidth.
Common questions
Will my image lose quality when resized?
When downscaling (making smaller), quality is preserved well thanks to high quality canvas smoothing. When upscaling (making larger), you cannot create detail that was not in the original, so the image will appear softer. For high quality upscaling, dedicated AI upscalers exist but they are a different category of tool.
Why is my output a JPG even though I uploaded a PNG?
The resizer outputs JPG by default for smaller file sizes. If you need lossless PNG output to preserve transparency or sharp edges, use a separate PNG conversion step.
Can I resize multiple images at once?
The current resizer is single-image only because most resize jobs need different dimensions per image. For batch downscaling at the same percentage, use the image compressor with a custom level instead.
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