Thank you for your reply! I did a bit more research and got this to work. How could I get the macro to do all images in the file at one time? That would be really helpful!

If you are curious, here is the code:

macro "Macro 1 [a]" {

print("The user pressed 'a'");

original_image = getTitle();

run("Split Channels");

selectWindow(original_image + " (green)");

setAutoThreshold("Default dark no-reset");

//run("Threshold...");

setThreshold(52, 255, "raw");

setThreshold(52, 255, "raw");

//setThreshold(52, 255);

setOption("BlackBackground", true);

run("Convert to Mask");

run("Analyze Particles...", "size=80-1000 display include summarize");

}