Vipsdisp can display huge (many, many gigabyte) images quickly and without
using much memory.

As well as the usual PNG, JPG, TIF, PDF, SVG, WEBP, JP2, JXL, QOI and GIF,
it supports many scientific and technical image formats, including SVS,
MRXS, OpenEXR, FITS, Matlab, NIfTI, Analyze, and PFM. It supports and
translates HDR metadata between JPG, PNG, AVIF and JXL, though there's no
HDR display yet.

Vipsdisp supports pixel types from 1 bit mono to 128-bit double precision
complex, you can convert image formats, it support copy-paste and drag-drop,
and it has a range of useful visualisation tools and display modes.

vipsdisp includes a very simple "paintbox" you can use to annotate images.
It can paint on images in all these numeric formats.