I have created an image for all the compose options.
The final image size and image meta-data will be from the destination image.

More detailed explanations can be found at Anthony's imagemagick example site


circle.gif
wedge.gif
Over
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with over.
Clear
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with clear.
Src
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with src.
Dst
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with dst.
Src-over
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with src-over.
Dst-over
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with dst-over.
Src-in
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with src-in.
Dst-in
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with dst-in.
Src-out
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with src-out.
Dst-out
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with dst-out.
Src-atop
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with src-atop.
Dst-atop
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with dst-atop.
Xor
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with xor.
Copy
<?php 
$cmd = "wedge.gif circle.gif -gravity northwest -compose $value -matte";
exec("composite $cmd output.gif");
?>
Replace $value with copy.


<?php 
$cmd = "$input small.jpg -gravity center -compose screen -matte";
exec("composite $cmd output.jpg");  
?>
Compose images using screen and a Large background jpg and Small foreground jpg. This is to show the way the image size will change depending on which image is called first.


Large background jpg
Small foreground jpg
Color-burn
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with color-burn.
Multiply
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with multiply.
Screen
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with screen.
Plus
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with plus.
Add
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with add.
Minus
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with minus.
Subtract
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with subtract.
Difference
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with difference.
Exclusion
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with exclusion.
Darken
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with darken.
Lighten
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with lighten.
Linear-dodge
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with linear-dodge.
Linear-burn
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with linear-burn.
Color-dodge
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with color-dodge.
Hard-light
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with hard-light.
Linear-light
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with linear-light.
Soft-light
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with soft-light.
Pegtop-light
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with pegtop-light.
Vivid-light
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with vivid-light.
Pin-light
<?php 
$cmd = "small.jpg $input -gravity center -compose $value -matte";
exec("composite $cmd output.jpg"); 
?>
Replace $value with pin-light.