How to Resize an Image Online Free — Exact Pixels or Percentage
Resizing images is necessary for profile pictures (which must be square), email signatures (limited pixel dimensions), website banners (specific aspect ratios), and attachment size limits. PDFBro resizes images to any dimension in seconds — no Photoshop, no GIMP, no installations.
Free Online Tool
Resize Image
Resize images to exact pixel dimensions
How to Resize an Image in 3 Steps
- 1
Upload your image(s)
Upload one or multiple images (JPG, PNG, WebP, etc.).
- 2
Set your target size
Enter exact pixel dimensions (width × height), or set a percentage scale (e.g., 50% to halve the size). Toggle 'Lock aspect ratio' to prevent distortion.
- 3
Download resized images
Download individual images or all resized images as a ZIP file.
Aspect Ratio — The Most Important Setting
Aspect ratio is the width-to-height proportion of an image. Changing it without care causes distortion — making people look stretched or squished.
Lock aspect ratio (recommended): Enter just the width and the height calculates automatically. The image scales proportionally with no distortion.
Unlock aspect ratio: Use only when the target container requires exact dimensions that differ from your image's natural proportions. This will distort the image — crop instead if possible.
Common Standard Sizes
Social media covers: Facebook 820×312px, LinkedIn 1584×396px, Twitter/X 1500×500px
Social media posts: Instagram 1080×1080px (square), 1080×1350px (portrait), 1080×566px (landscape)
Email signature images: 200–300px wide, proportional height
Website hero images: 1920×1080px (Full HD)
Thumbnails: YouTube 1280×720px, blog post 800×450px
Print at 300 DPI: A4 paper = 2480×3508px
Resizing vs Cropping — Which Should You Use?
Resize scales the entire image to a new size. The full image content is preserved but at different dimensions.
Crop cuts away portions of the image and keeps a specific area at its original resolution — or adjusts it to a new size.
For example: to fit a landscape photo into a square profile picture, don't resize (it'll distort) — crop to 1:1 aspect ratio instead. PDFBro's Crop Image tool handles this perfectly.
Pro Tips
- 1
When resizing for web, resize then compress — a 1920px wide image compressed at 80% JPEG is optimal for most websites.
- 2
For batch resizing to the same dimensions, upload multiple images and apply identical settings to all at once.
- 3
Enlarging images beyond their original size causes pixelation. Always resize down, not up, for quality results.
Frequently Asked Questions
Can I resize without distorting the image?
Yes. Lock the aspect ratio option preserves proportions. You enter one dimension and the other calculates automatically.
What's the maximum image size PDFBro can handle?
PDFBro supports images up to 30 MB per file.
Can I resize multiple images at once?
Yes. Upload up to 20 images and apply the same dimensions to all in one batch.
Does resizing reduce image quality?
Reducing size maintains quality. Enlarging beyond the original can cause pixelation since new pixels are generated artificially.