Set image DPI without resizing

No. dpi (dots per inch, also written ppi) is a number stored in the file header that tells printing and layout software how many pixels to place per inch of paper. It does not change the width or height in pixels, the picture itself or how a web page shows it. This tool changes only the header field, so the pixel dimensions and the visual content are identical before and after.

Because pixel size and dpi are two separate values. A large photo exported from a browser, a phone or a design tool can carry a density field of any value, or no density field at all, and software that reads the header reports what it finds there. Amazon's technical table lists image size in pixels and resolution in dpi as two different lines. This tool sets the second line; it cannot and does not touch the first. In our own testing, files exported by browsers and phones frequently carry no density field at all — that is a property of those exporters, not something any marketplace page states.

Amazon's product image guide (G1881) lists "At least 72 dpi" as the resolution line of its technical table; the Amazon Seller Central image technical requirements page carries the same technical table, and both official pages are listed under sources below with the date we checked them. The table has separate lines for pixel size and file format, so writing 72 dpi or more matches the value on the resolution line and nothing else. Pixel size, format, background, file naming and every other Amazon rule are unaffected by this tool — the Amazon resizer linked below carries the pixel lines with their own sources, and the linked official pages are the authority.

No. The official Image guidelines & requirements page lists file format, colour format, file size, bit depth, pixel dimensions (2200px x 2200px, printed as a Pixel Dimensions value with neither the word minimum nor maximum), a 1500px x 1500px minimum for zoom, a 100px x 100px swatch size, aspect ratio and background. It has no resolution, ppi or dpi line. The figure often quoted elsewhere is listed above under numbers that are not on the official page.

No. Etsy's help article gives its guidance in pixels — it recommends listing photos with a width and height of at least 2000 pixels, and says the first photo should be at least 635 pixels wide and high "to avoid showing up lower in searches"; the same page says "Avoid square crops", so the 2000 pixel figure is a recommendation that applies to width and height separately, not an instruction to make the image square. It also warns that images larger than 1MB "may not finish uploading, especially on a slower internet connection" — a warning, not a hard cap. It states no PPI figure. The figure quoted elsewhere is listed above under numbers that are not on the official page.

72 is the only dpi figure on the official marketplace pages we checked on 2026-09-19 (Amazon: "At least 72 dpi"). We do not ship a second, higher preset, because no marketplace page listed here asks for one — type the value your printer or client specifies into the custom field. The custom field takes any whole dpi value from 1 to 65535. That range is this tool’s own, set by the 16-bit density field a JPEG’s JFIF header uses, not a marketplace figure, and a value outside it is reported back on the file’s own row instead of being written.

JPEG and PNG only. For a JPEG the value is written into the JFIF header (density unit set to dots per inch); if the file has no JFIF header, one is added. For a PNG the value is written into the pHYs chunk, converted to pixels per metre, which is the unit PNG uses, so the value shown back to you is rounded to the nearest whole dpi; a JPEG that stored its density in dots per centimetre is reported as the nearest whole dpi for the same reason. WebP, GIF, TIFF, BMP, HEIC and other files are reported as unsupported and left unchanged.

No. The number of pixels is fixed by the file and this tool never resamples. Amazon's page also says not to artificially enlarge small images. If your file is below a platform's pixel minimum, a new photo or export at a larger pixel size is needed; changing the dpi header does not change that.

For a JPEG the JFIF density fields are set, and a JFIF header is added if the file has none; for a PNG the pHYs chunk is written. If the file already carries EXIF resolution tags — XResolution, YResolution and ResolutionUnit, in a JPEG's Exif segment or a PNG's eXIf chunk — they are updated in place to the same value, because some applications read those before the JFIF or pHYs field. No EXIF tag is created where none existed, so a file that carried no EXIF resolution tag still carries none. One field is deliberately left alone: if your file carries an XMP packet holding a tiff:XResolution value, we do not rewrite it, because the XMP block is left byte-for-byte unchanged. Some Adobe applications read that value first, so they can still report the old number — a JPEG saved out of Photoshop is the usual case, and re-saving it from that application is what updates the XMP value. Otherwise a stale reading is usually a cached thumbnail or a preview made before the change: close and reopen the file, or clear that application's preview cache. The result row shows both the previous and the new value read from the JFIF or pHYs field.

Amazon (US) is the only marketplace with a dpi value on the official pages we checked on 2026-09-19. Walmart's official Image guidelines page states no ppi or dpi value anywhere, and Etsy's official help article contains no PPI figure; both are set out above under numbers that are not on the official page, each with its source. No dpi or ppi line appears on the official eBay, Shopify or Shopee pages we checked either, so this tool has nothing to match on those platforms. We do not repeat their figures here, because this page carries no source line for them: the eBay, Shopify and Shopee tool pages linked below each state that platform's own rules with the official URL, the quoted text and the date we checked it, and the page on where the official image specs disagree sets out Shopify's two official pages side by side with both quotes. For Shopee, the Singapore seller site is the only market we checked.