Use this image resizer for printing to set exact pixels or a percentage in your browser. JPG, PNG, and WebP stay on your device from upload to export.
Resize to the pixels you need, inspect that exact generated file, then download it or continue to Rasterbator; use the DPI Calculator for paper-fit checks.
JPG, PNG, or WebP
Resizing stays on this device: browser Canvas decodes, resizes, and exports the image locally. Continue to Rasterbator only when you want to pass the generated Blob into a local draft.
Exact pixels, percentages, or print paper targets
Uses A4 210 × 297 mm, A3 297 × 420 mm, and Letter 8.5 × 11 in. The preset follows the source orientation and leaves your current aspect-lock setting unchanged.
Use the preview as a shape and framing check, not as proof that enlargement created new detail. Compare the source and output for stretched subjects, unexpected aspect-ratio changes, transparent areas, and the edges you expect to keep. A proportional downsize should preserve the composition; an intentionally unlocked resize may visibly change it. For print preparation, catching those differences before poster layout is more useful than judging sharpness from a scaled browser preview alone.
An image resizer for printing is most useful when it turns an oversized or awkward source into a deliberate working file before you decide the tiled poster layout. The goal is not to guess one universal print resolution; it is to remove unnecessary pixels, preserve the intended proportions, choose an export format, and then pass a known-size file into the next check. That keeps resizing separate from the DPI decision while making the handoff between the two tools explicit.
Use an exact target or percentage when the original carries more pixels than the poster workflow needs. For example, a 3000 × 2000 source becomes 1800 × 1200 when you set width to 1800 with aspect lock.
That preserves the 3:2 source shape, but it does not magically make the file an A-series paper ratio. Take the 1800 × 1200 result into the DPI Calculator to see how it fits an A4 plan.
As orientation points, the calculator uses about 2481 × 3508 px for A4 at 300 DPI and 3508 × 4961 px for A3 at 300 DPI; those are print references, not mandatory resize targets.
Lock the original aspect ratio when the photo, illustration, or poster artwork should keep its composition. Changing only width then calculates the matching height from the source ratio, and changing height does the same in reverse.
Unlock the ratio only when independent dimensions are intentional, because forcing a 3:2 image into a different width-to-height shape stretches the pixels rather than cropping them.
If your paper ratio differs from the image ratio, decide later whether you prefer margins or cropping instead of disguising that mismatch with distortion.
Use in Rasterbator passes the generated file—not the original—into the existing local draft-project workflow. The draft records the resized width and height with the same Blob that was previewed, so the poster maker starts from the dimensions you just approved.
This is useful when a camera image is much larger than the working poster needs: you can reduce it once, confirm the output, and continue without selecting or uploading the source again.
The draft stays local and does not appear as a normal saved project until the poster workflow turns it into one.
Select or drop a JPG, PNG, or WebP. The browser reads the real source dimensions locally, which gives you a reliable starting point before changing anything.
Note the original width and height, especially when the file came from a phone, camera, design export, or screenshot where the pixel count may be much larger than the dimensions you actually need for a poster workflow.
Choose an exact width and height, keep the original ratio locked for proportional resizing, or use a percentage shortcut from 25% to 200%. A 50% preset halves each axis, so a 3000 × 2000 source becomes 1500 × 1000.
Before exporting, confirm the displayed output dimensions and scale rather than relying on the visual preview alone; the numeric result is what the generated file and later handoff use.
Finish the print-resizing workflow by checking four things: output dimensions, aspect ratio, format, and the generated file you are about to keep.
Preserve PNG when transparent areas must remain transparent; choose JPG for photo-heavy images when transparency is unnecessary and a smaller file is usually more practical.
Download that exact generated Blob or send it to Rasterbator as a local draft. If paper size or viewing distance is the next decision, use the DPI Calculator to verify whether those pixels are enough rather than guessing inside the resizer.
