Welcome, Ella.
As others have noted, spray adhesives have a poor reputation among framers, because there is a better adhesive for almost any need.
Yes, the sprays' solvents are chemically toxic, but also, the overspray particulate gets into your lungs and never comes out. Sprays are the least-permanent adhesives commonly available for framing applications - dry mounting, wet mounting, and mechanical mounting are all better choices. Sprays are generally the framer's most expensive adhesives, too.
Many of us have seen spray adhesives fail, and most of the failures you experience, which inspired this thread, probably were spray-adhesive mounts. In that case, applying more spray adhesive would be a temporary fix, at best.
The problem with using a different adhesive to repair a failed adhesive mount is that you have no way to know about the compatibility of the two adhesives. That is, the new adhesive might not bond to the old adhesive's residue, assuring early failure for the repaired mount.
The best action would be to reproduce the image on a new substrate and start over with all-new materials. That way, you know exactly what you are dealing with.
Or, if the image can not be replaced, or duplicated by scanning/photographing & printing, then do your best to remove the entire mount, remove the adhesive residue, and mount it to a new substrate with a new adhesive. On the few occasions when I have had to do that, I have used heat activated adhesive applied to foam board, such as my favorite dry mounting substrate, Kool Tack.
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