Glass buttons, possibly old

I found some interesting buttons in my grandmothers sewing stuff, and am hopeful I can get some information about them. I'm unsure of age, and know there is sewing stuff from 1-100+ years old.

There are some buttons that I'm fairly certain are glass, and have different images on them. I looked at the pictures with magnification, and these ones don't show the familiar dotted patterns that printed stuff. I'm wondering if they may be hand painted, but seem quite detailed for such tiny images. Could there have been printed using something like silk screen?

The holes in the back are not of glass, but of a metal.

I love some of these buttons and am thinking about putting some on a sweater I'm making, but am concerned they may be special and I don't want to ruin them if that's the case.