How It Works
Unlike browser-based tools that process images on your device, kinja-img.com resizes images server-side via URL parameters. Upload once, then generate as many sizes as you need just by changing the URL.
- Upload your image at kinja-img.com/resize-image
- Get your image URL (e.g.
https://i.kinja-img.com/img/.../photo.jpg) - Add parameters:
/img/w_800,h_600,c_fit/photo.jpg - The server resizes on the fly and caches the result
One upload, unlimited sizes. No re-uploading for every dimension you need.
Three Resize Modes
The c_ parameter controls how the image adapts to your target dimensions:
- c_fit (recommended) — fits the image within the given width and height while maintaining aspect ratio. The result may be smaller than the specified dimensions on one side, but nothing is cropped or distorted.
- c_fill — fills the exact dimensions you specify. If the aspect ratio doesn't match, edges are cropped. Use with gravity (
g_center,g_north) to control which part stays visible. - c_scale — stretches or squeezes the image to fit exactly. This will distort the image if ratios don't match. Rarely recommended, but useful when you need pixel-exact output.
URL Parameter Reference
All parameters are comma-separated in the URL path:
https://i.kinja-img.com/img/{params}/filename.jpg
w_800 → width 800px
h_600 → height 600px
c_fit → fit mode (maintain ratio)
c_fill → fill mode (crop to fit)
c_scale → scale mode (stretch)
q_70 → quality 70% (1-100)
f_webp → convert to WebP formatYou can use width alone, height alone, or both together. Maximum output dimension is 2000×2000 pixels.
Quality & Format Control
Combine resizing with quality and format parameters for optimal results:
- q_85 — good balance of quality and file size for most photos
- q_70 — noticeable compression but 40-60% smaller files, great for thumbnails
- f_webp — convert to WebP for an additional 25-35% size reduction
# Resize + compress + convert in one URL
/img/w_1200,c_fit,q_80,f_webp/photo.jpgDefault quality is 80 if not specified.
Practical Examples
Common resize scenarios:
# Social media thumbnail
/img/w_400,h_400,c_fill/photo.jpg
# Blog header image
/img/w_1200,c_fit,q_85/photo.jpg
# Email-safe small version
/img/w_600,c_fit,q_70,f_webp/photo.jpg
# High-res but compressed
/img/w_2000,c_fit,q_75/photo.jpgAll formats supported: JPG, PNG, GIF, and WebP. Max upload size is 50MB per image.