Image Cropping and Dimensions

Tried an experiment based on some of the posts I have read regarding cropping images within Corona.

The main thread said to try this:

local myImage = display.newImage(“myPhoto.JPG”,0,0)
local mask = graphics.newMask(“mymask.png”)
myImage:setMask(mask)
display.save(myImage,“myImage.jpg”)

So suppose my Image is 320x480 and my mask is 100x100. (It is the circlemask from the fishy demo scaled down by half)

The resulting saved image is 181x181.

Can anyone tell me where this value comes from?

Also, if I used a mask <= 50x50 the resulting image is totally jacked up. It is no longer a circle.
Double Also… if I save the image to png, the resulting file format is unreadable by fireworks or photoshop.
Thanks! [import]uid: 69863 topic_id: 15692 reply_id: 315692[/import]