FixTools makes online image resizing simple, fast, and completely free.
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Resize by pixels or percentage
Lock aspect ratio to avoid distortion
No watermark on resized images
Works on any device, no sign-up required
Drop the Image Resizer into any page — blog post, product docs, intranet, school portal — with a single line of HTML. Your visitors get the full tool, processed entirely in their browser. No backend, no uploads, no signup.
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></iframe>Attribution-friendly: a small "Powered by FixTools" link appears in the embed footer.
When you resize an image for the web, you work in pixels because every modern screen measures everything in pixels. A pixel is the smallest addressable unit of a display. When someone says their image is 1920 wide, they mean 1920 pixels across. DPI, which stands for dots per inch, is a print concept that describes how densely those pixels are packed onto physical paper or onto a physical screen panel. On a computer monitor or phone, the DPI metadata stored inside a JPG or PNG does not change how large your image looks in a browser. Only the pixel count does. A 1000 by 1000 pixel image looks the same physical size on screen whether the file metadata says 72 DPI, 96 DPI, or 300 DPI, because the browser ignores that field entirely and reads only the actual pixel dimensions out of the file header.
The confusion between pixels, DPI, and inches trips up many people coming from print workflows. A 300 DPI image at 4 by 6 inches contains 1200 by 1800 pixels. If you take that same file and change the DPI metadata to 72 without resampling, the pixel count stays at 1200 by 1800. Nothing about the image data has changed. The file will display identically in a browser, in social media uploads, and in slide decks. DPI metadata only matters when a printer driver uses it to calculate how large to print the image on physical paper. For every web, social, email, or app screen purpose, ignore DPI completely and focus on the pixel dimensions, because that is the only number that drives sharpness and file size in those contexts.
Retina and high-DPI screens add one more layer to understand. A modern iPhone Retina screen might display at 458 physical pixels per inch, but web content is still specified in CSS pixels, which are logical units rather than physical ones. A 1000 pixel wide image set to display at 500 pixels of CSS width will look sharp on Retina because iOS uses two physical pixels for each CSS pixel along that span. This is why designers often prepare images at double the intended display size. A 1200 pixel image intended to display at 600 CSS pixels will appear razor-sharp on any high-DPI device without requiring special settings, srcset tags, or media queries. The cost is a slightly larger file, but for most photographic content the size increase from double resolution at the same JPG quality is much smaller than people expect.
When deciding what pixel dimensions to resize to, work backwards from the largest size the image needs to display at on the largest screen you care about. A blog hero image that maxes out at 1100 CSS pixels wide on a desktop layout should be exported at 2200 pixels wide to cover Retina. A product thumbnail that appears at 200 CSS pixels in a grid can be safely exported at 400 pixels. Going beyond two times the display width rarely produces a visible benefit and costs file size and load time. For documents, presentations, and email attachments where Retina is irrelevant, the target pixel size matches the display size one to one, and any image larger than the display container is wasted bandwidth that you can recover with a quick resize.
Upload your image, enter your target width and height in pixels, and click Resize. Enable "Lock Aspect Ratio" to prevent distortion.
Step-by-step guide to resize image online free:
Upload your image
Click the Open Image Resizer button on this page and either drag a file from your desktop into the upload zone or tap to pick a photo from your phone gallery. Most common formats are accepted, including JPG, PNG, WebP, and GIF, so you can start from a camera photo, a screenshot, or a download without any prior conversion step.
Enter target dimensions
Type the width and height you want in pixels, or switch to the percentage field and enter a scale factor like 50% or 25%. Percentage scaling is handy when you do not know the exact target pixel count but want the image roughly halved or quartered. Both inputs update the preview before you confirm so you can sanity check the output size.
Lock aspect ratio
Tick the Lock Aspect Ratio checkbox so the tool fills in the matching dimension automatically when you change one side. This keeps faces, logos, and product shots looking natural rather than stretched. If you specifically need a non-proportional shape, for example a 1000 by 1000 thumbnail from a wide photo, leave the lock off and accept the stretch or pre-crop to a square first.
Resize and download
Click the Resize button and wait for the preview to refresh. When you are happy with the output, hit Download to save the file to your computer or phone. The output keeps the original file format by default, but you can change to JPG, PNG, or WebP from the format selector if you want a smaller or higher quality file than the source.
Common situations where this approach makes a real difference:
A web developer resizes product photos to 800 by 600 pixels before uploading to their e-commerce store.
The developer is migrating a Shopify catalog of 200 products and notices that the supplier-provided photos are all 4000 pixels wide, which makes category pages take six seconds to load on mobile. By batch resizing every photo to 800 by 600 pixels at 85 percent JPG quality, the average product image drops from 1.2 megabytes to about 70 kilobytes, and the category page load time falls under two seconds. Conversion rate on mobile climbs noticeably in the following week because shoppers stop bouncing on the slow grid.
A blogger resizes a 4K camera photo to 1200 pixels wide before embedding it in a WordPress post.
The blogger imports a RAW photo from a Sony mirrorless camera, exports a JPG at the camera native size of 6000 pixels wide, and realises WordPress will happily embed the giant file at full size and ruin both the page load and the layout. Resizing to 1200 pixels wide before upload keeps the image sharp on Retina laptops at the 600 pixel display size used by the blog template, while cutting the file from eight megabytes down to about 220 kilobytes, which is friendly to mobile readers on cellular data.
A social media manager batch resizes brand photos to a consistent 1080 pixels wide before scheduling posts.
The manager runs the brand accounts on Instagram, Facebook, and LinkedIn, and every platform compresses uploads differently. By standardising on 1080 pixels wide at 90 percent JPG quality before scheduling through Buffer, the photos arrive at each platform already at the recommended dimension, which means the platform-side compression has less work to do and the final feed image looks sharper than if the source had been a 4000 pixel original that the platform downscaled aggressively on its own servers.
A parent resizes a school report photo from 12 megapixels down to 1500 pixels wide before emailing.
The parent needs to email a scanned permission slip and a photo of the child to a summer camp registrar who has warned that the inbox blocks attachments above five megabytes. The original phone photo is 11 megabytes. After resizing to 1500 pixels wide the file is around 400 kilobytes, easy to attach to a single message along with the PDF, and still sharp enough that the registrar can read every detail. The whole exchange takes a minute rather than the back and forth that would otherwise be needed.
Get better results with these expert suggestions:
Always resize by pixel count, not DPI
When working for the web, social, or email, set your target width and height in pixels and ignore any DPI settings or 72 DPI checkboxes. Changing the DPI metadata without resampling pixels does absolutely nothing to how your image displays on a screen. Tools that advertise 72 DPI web optimisation as a feature are only rewriting a metadata tag and leaving the pixel data unchanged, which means no real change in file size or sharpness.
Downscale in one step for sharpest results
If you need to go from 4000 pixels to 1000 pixels, do it in a single resize operation rather than stepping down through several intermediate sizes. Multi-step downscaling can introduce visible softness as the resampling algorithm smooths data at each stage, and the errors compound. A single-pass resize from the original full-resolution source to your final target gives the cleanest output and runs faster too, since you avoid loading and re-encoding intermediate files.
Keep your original file
Always resize a copy, not the original. Once you save over an original at smaller dimensions, the pixel data you removed is gone permanently and there is no way to recover the lost resolution. Store originals in a clearly labeled folder, perhaps named originals or raw, and export resized versions to a separate output folder. If you ever need a different target size later you can come back to the original and resize again without quality loss.
Use PNG output for graphics, JPG for photos
PNG is lossless and ideal for logos, screenshots, diagrams, and graphics with flat colours, sharp edges, or text. JPG compresses photographic content far more efficiently because of how its discrete cosine transform handles smooth gradients. Resizing a photo and saving as PNG produces a much larger file than necessary, while resizing a logo and saving as JPG adds visible compression artefacts and halos around hard edges, especially around text and contrasting colour boundaries.
More use-case guides for the same tool:
Open the full Image Resizer — free, no account needed, works on any device.
Open Image Resizer →Free · No account needed · Works on any device