The Transparent color space behaves uniquely in that it perserves the matte channel of the image if it exists.
The -colors or -monochrome option is required for this option to take effect.
-comment "%m:%f %wx%h"
over
in
out
atop
xor
plus
minus
add
subtract
difference
bumpmap
replace
-label "%m:%f %wx%h"
Letter 612x 792
Tabloid 792x1224
Ledger 1224x 792
Legal 612x1008
Statement 396x 612
Executive 540x 720
A3 842x1190
A4 595x 842
A5 420x 595
B4 729x1032
B5 516x 729
Folio 612x 936
Quarto 610x 780
10x14 720x1008
To position a GIF image, use -page +LEFT+TOP (e.g. -page +100+200).
The optional mask can be used to provide matte information for composite when it has none or if you want a different mask. A mask image is typically grayscale and the same size as composite. If the image is not grayscale, it is converted to grayscale and the resulting intensities are used as matte information.