the confusing thing with this is there are two places in the dialog where the term "icon" are used
1)
dialog [-l] name {
title "text"
icon filename, index
size x y w h
option type (dbu, pixels, notheme)
this first one allows the icon of the dialog itself to be changed from the mIRC default to one of your own choosing. Note the location in the dialog table and the "index" switch
2)
icon id, x y w h, filename, index, style (noborder top left bottom right)
this allows you to place images (ico, bmp, jpg) in the client area of the dialog.
sample
dialog icon {
title "Icon Test"
icon "C:\windows\system32\calc.exe", index
size -1 -1 100 50
option dbu
icon 1, 20 20 32 32, "C:\windows\system32\calc.exe", noborder
}
note I used " around the path\filename though I did not need to as there were no spaces in the path, had I chosen an exe as the icon source and it was say in the c:\program files\ folder the " would be needed