Depending on the snail the eggs are a rather firmly attached blob of transparent slime. And i don't know how they do it with some snails it is attached with a hard shell like base with a slimy blob on top. Also this slimy blob, feels more rubbery than slimy.
Other snails for example Nerite it's more looking like little creme colored dots all over the place that are almost impossible to remove without a sharp tool.
In your picture it is hard to see, but it more looks like foamy/slimy.. Could be a bacterial biofilm.. That can start out as a slimy blob too and looking like snail eggs.. But bacteria can release gasses like methane or co² and that can make it look foamy after a while.