how many layers do others use? i seem to be having issues when flattening images. what am i missing.

on a second note, how do others decide on the opacity level ? that might be the problem i'm having.

I think I have 20 -30 layers on most of my boards, but I use a separate layers for just about every object, which makes things easier to change. 

Opacity depends on what it is, and how you want it to look.  Someone suggested I set the whole hexes board to 70-80% and it came out fantastic.  If it's a texture or a "ghost" design I'm usually around 24-27%.   If you need a whole, 0% opacity. 

What program are you working with?

i typically run 75% opacity when i use it. have had to go as low as 25 a few times.
i haven't had more than a dozenish layers on the boards i've used before i start merging things.

i use paint. does it matter how many layers you flatten at a time?

no, but if you're doin a layer with opacity, there's a certain order in which it needs to be in. try merging everything except the one opaque layer. then merge, if it doesn't stay opaque, then undo swap which layer is on top and retry

No. When you flatten layers, all the visible stuff becomes one image, and anything you can't see disappears into the ether. 

Can't you just save directly as a .png? At least in GIMP, when you save as a .png the program automatically flattens the image so that it appears exactly as it does on the monitor display.

thanks everyone i think i get it now. total brain fart. :)

I almost never merge -- you never know when you might want to tweak something. It makes for tricky file management sometimes, but..

Aye, in the past I've kept a lot of layers rather than merging.  I've had upwards of 60-70+layers for some boards (which normally include Scenarios too).

The only time to merge is in the creation of the the .png files for upload. Other than that, I keep everything in layers, often dozens of them depending on the board.