Contact
Bug reports, feature requests, "this tool ate my PNG" stories, and "this conversion is wrong" reports are all welcome. The fastest way to get my attention is email with a small sample file attached (one I can use to reproduce — preferably one I can keep, but not required).
Reporting a bug
A useful bug report has three things: (1) the URL of the tool you used, (2) what you expected vs. what happened, and ideally (3) a sample file that triggers it. The third one is the most valuable — without a reproducer, I'm guessing.
Files attached to email reports are deleted once the bug is fixed (or once I confirm I can't reproduce it). If your file contains anything sensitive, please redact or synthesise an equivalent; the privacy policy on the site only covers what happens in the browser, not what you choose to send me.
Requesting a tool
Before suggesting a new PNG tool, check the homepage and the footer to make sure it's not already there in slightly different form. The tools that currently exist solve problems I've personally hit; the bar for adding more is "useful enough that I'd reach for it again next month."
What this site doesn't do
It does not OCR scanned PNG and image files (yet — Tesseract.js is heavy and would slow page loads for everyone), does not bypass user-password encryption, and does not "compress" PNG and image files in a way that's worth shipping (browser-side recompression can't compete with Ghostscript / qpdf). Each of those is a deliberate gap, not an oversight.
Other sites
Sister tools for adjacent file formats: csvkit.org (CSV), jsonlkit.com (JSONL / JSON Lines), tomlkit.org (TOML), geojsonkit.org (GeoJSON). Same browser-only philosophy.