As with many things in programming, the specific definitions of these words will be tied directly to whatever IDE you're using. That being said, the general experience I've had with these words in programming have been:
image, in general, tends to be a fairly general term. It can refer to a photograph, a line drawing, a logo, text rendered in an image format, etc.
glyph, on the other hand, is usually close to the typographic sense of the word "A representation of a letter, character, or symbol". Examples might be company logos, stylized lettering as a header, etc. I've never seen it used for a photograph (well, potentially a photograph of a logo).
If the two are used in the same setup, my expectation would be that image would actually serve a less general role, instead representing pictures that were not glyphs.