[Plugin: PostMaster] PNG attachments?

I have Postmaster installed and working. However I find that if I attach a PNG image, it gets lost. JPG’s post just fine (haven’t tried any other img filetypes), but whenever I try to attach a PNG, the image gets lost.

Is this normal for the plugin? (ie… just doesn’t recognize PNG’s)

I like to post images from my BB, so all my camera pics are JPG’s anyway, however I ran into a situation where somebody mailed me a PNG file and I wanted to attach it to a blogpost.