Image Thumbnail
Shrink a picture to a thumbnail.
How to use Image Thumbnail
Free thumbnail tool: scale a photo so its longest side fits a size you set, keeping quality with the canvas.
Open Image Thumbnail on toolpermarket and fill in the inputs the tool asks for.
In the Image field, select a picture to shrink. The longest side is what gets scaled.
In the Max dimension field, set the target size in pixels. 200 to 400px suits most thumbnails.
Press Make thumbnail to compute the result. The output appears immediately below the form. Adjust the inputs and recalculate as many times as you need.
Read the result and use it as needed. If the number looks off, re-check your inputs and run it again — the math is deterministic, so the same entries always return the same answer.
Worked example. A 4000px photo set to a 200px max becomes a crisp small thumbnail keeping the original ratio.
Tips for accurate results.
Keep the aspect ratio; the tool does it for you.
Use PNG for graphics, JPG for photos.
Smaller max sizes load faster on listings.
When to use Image Thumbnail. Generating previews for a gallery or list. Shrinking photos for faster page loads. Making consistent-sized icons from mixed sources.
When you actually reach for this
- You need a small preview version of a photo for a gallery or list.
- A form wants a tiny image and the full-size file is over the limit.
Where this tool stops being accurate
- A thumbnail is just a small resize; enlarging it later gives a soft, low-detail image.
- Keep the full original if you ever need print or detail; the thumbnail is display-only.
Frequently asked questions
Does making a thumbnail upload my photo?
No. The full image is loaded into the browser, scaled down on the canvas so its longest side matches your setting, and downloaded. The original stays on your device and nothing is sent to a server during the process.
Will the thumbnail keep the same proportions?
Yes. The tool scales by the longer side and computes the shorter side from the original aspect ratio, so the picture is not stretched or squashed. You only control the maximum dimension, and the shape is preserved automatically.
What size should I pick for web use?
Around 200 to 400 pixels on the long side covers most thumbnails and keeps files tiny for fast loading. Go smaller for dense grids and larger if the thumbnail is the main view; the canvas preserves quality at whatever size you choose.
Can I enlarge a thumbnail back to full quality?
No. It only holds the small version, so upscaling looks soft. Keep the source file for anything beyond preview.