What does Image DPI Converter do?
Tubelexity is a technically honest image DPI converter: DPI metadata controls intended print density, while pixel dimensions control actual sampled detail. Metadata-only mode writes JPEG JFIF density or PNG pHYs data without changing pixel dimensions. Resample mode changes pixel dimensions in proportion to DPI to preserve physical print size, but does not claim to invent detail.
How to use Image DPI Converter
- 1Choose a JPG, PNG or WebP image and review pixel dimensions and detectable DPI.
- 2Confirm the current DPI, then select 72, 96, 150, 300, 600 or a custom target.
- 3Choose metadata-only mode or resample pixels to preserve physical print size.
- 4Review old and new dimensions and print size, then export when the format supports correct DPI writing.
Supported inputs and outputs
Inputs
JPEG/JPG, PNG, WebP for inspection only
Outputs
JPEG with JFIF DPI metadata, PNG with pHYs resolution metadata
Practical uses
- Setting 300 DPI for print workflows
- Correcting missing print-density metadata
- Calculating inches or centimeters
- Resampling for a fixed physical print size
Browser and media limitations
- Changing metadata alone does not add pixels or image detail.
- WebP export is disabled because this pipeline cannot reliably write standard WebP DPI metadata.
- Resample mode re-encodes image pixels.
- Very high DPI resampling can exceed Canvas and browser memory limits.
- A print application may apply its own scaling rules.
How local processing works
Image bytes are inspected and processed with lightweight browser APIs in this tab. These tools do not load FFmpeg and do not upload the image or metadata.
Frequently asked questions
Does converting 72 DPI to 300 DPI improve quality?
No. Metadata-only conversion keeps the same pixels; it changes intended print density, not detail.
What does preserve physical print size mean?
Pixel dimensions are multiplied by new DPI divided by old DPI, keeping width and height in inches unchanged.
Which formats get real DPI metadata?
JPEG uses JFIF density fields and PNG uses a pHYs chunk. WebP writing is disabled.
Can I calculate centimeters?
Yes. Switch the print calculator between inches and centimeters.
Is metadata-only JPEG conversion lossless?
The compressed image data is retained; only the JFIF density segment is added or updated.