FAQ
Frequently Asked Questions
Everything you need to know about DPI, image resolution, and how our tool works.
DPI stands for "Dots Per Inch." It is a measurement of spatial printing or video dot density — how many individual dots of ink or pixels can be placed in a line within the span of 1 inch. Higher DPI means more detail and sharper output. For digital displays, 72–96 DPI is standard. For professional printing, 300 DPI is the minimum requirement.
No. Changing the DPI metadata does not add new pixels — it changes how software interprets the existing pixels. Think of it like this: a 1000×1000 pixel image at 72 DPI tells a printer to spread those pixels over 13.8 inches. At 300 DPI, the same 1000×1000 pixels would fill just 3.3 inches — much denser and sharper in print. To truly add more detail, you would need AI-powered upscaling. Our tool updates the DPI tag so your image is rendered at the correct size when printed.
Yes, completely free — no sign-up, no subscription, no watermarks, no hidden fees. There are no limits on how many images you can process. The only technical limit is your browser's memory, so we recommend images under 50 MB for best performance.
Absolutely not. Everything happens inside your browser using JavaScript and the HTML5 Canvas API. Your image files never leave your device, never touch our servers, and are never stored anywhere. This is why we call it a privacy-first tool.
300 DPI is the standard for professional printing — brochures, flyers, business cards, photos. 600 DPI is used for very high-quality work like fine art prints or large-format banners. 150 DPI can work for newspapers or basic document printing. 72 DPI is for web/screen display only.
Our tool supports JPEG (.jpg/.jpeg), PNG (.png), and WebP (.webp) files up to 50 MB. The output file is saved in the same format as your input — JPEG in, JPEG out; PNG in, PNG out. WebP files are converted to JPEG for output.
Our tool writes the DPI into the standard JFIF (for JPEG) and pHYs (for PNG) metadata fields. Photoshop reads these correctly. If Photoshop shows a different value, try going to Image → Image Size → uncheck "Resample" and manually type in the DPI. Make sure you open the freshly downloaded file from our tool.
Yes! Below the preset buttons (72, 150, 300, 600), there is a custom DPI input field where you can type any value from 1 to 9600 DPI. This covers virtually all professional use cases, from low-resolution web previews to ultra-high-quality printing.
The file size change is minimal because we are only modifying a few bytes of metadata in the file header, not the actual pixel data. The file size may vary slightly due to re-encoding through the Canvas API, but it will be very close to the original size.
Yes! Our tool works on any modern browser, including mobile browsers on iOS and Android. Simply open the site, tap the upload zone to select an image from your photo library, choose a target DPI, and download the result.