Limit previews to images and videos/gifs. At least one video or image preview must not have flame particle textures on them, because flame colors and behaviors may change based upon textures. Any transferral of data prior to sale may result in you being scammed. We are not responsible if you do this. (To take a screenshot without your texture, open toribash, then delete your texture toribash/custom/[your name]/flame.tga, do /lp 0 [your name] or /lp 1 [your name], screenshot)
All flame sales should have at least one preview with the entire flame against the default white background. Different shaders may make flames appear differently, so for standardization, default shaders should be used unless it is requested otherwise.
I'll take pictures for you and post them.