A photo that looked right on one screen and noticeably duller, more saturated, or just "off" on another — or after being saved or converted — is usually a color profile issue, not a sign the image data itself was damaged. It's a genuinely subtle topic, but the core idea is simple once it clicks.
What a color profile actually is
A color profile is metadata embedded in an image file that describes exactly how its color values should be interpreted — essentially, a translation key between the numbers stored in the file and the actual colors those numbers are supposed to represent on a properly calibrated display. Two images can have identical underlying pixel values but display as noticeably different colors if they carry different color profiles (or no profile at all), because the numbers are being interpreted differently.
Why this causes visible shifts
The most common everyday case is an image using a wider color space (like Adobe RGB, common in professional photography) being viewed or converted somewhere that assumes the more common sRGB space instead. Colors that fall outside what sRGB can represent get compressed or shifted to fit, which can produce a visibly duller or altered result compared to how the image looked in its original wider color space.
Losing the profile entirely
Some conversion or editing processes strip the embedded color profile without properly converting the underlying color values to match — in that case, the numbers stay the same but the "translation key" for interpreting them correctly is gone, so whatever's displaying the image falls back to a default assumption that may not match what was originally intended.
What actually fixes it
A conversion tool that properly handles color profiles either preserves the original profile through the conversion, or performs a genuine color space conversion (correctly translating the underlying values, not just discarding the profile) when a format change requires one. This is worth being aware of specifically for professional photography work, where color accuracy across different software and devices genuinely matters.
Convert Image preserves embedded color profile data through format conversion. If you want to check exactly what profile and metadata an image currently carries, Image Metadata shows that information directly.