If I do the following
for root, dirs, files in os.walk(myDir):
for myFile in files:
with Image(filename=myFile
First things first - file a bug with wand. The wand.image.Image.destroy is not cleaning up wand.image.Sequence in the event an image sequence was allocated. Good find!
You are absolutely correct with main.sequence[0].destroy(); however, your only freeing the first allocated SingleImage in the sequence. So img.sequence[1:] is still setting in memory. A not-so-elegant solution would be to iterate & destroy all SingleImage's.
for root, dirs, files in os.walk(myDir):
for myFile in files:
with Image(filename=myFile) as img:
with Image(image=img) as main:
first = True
for frame in main.sequence:
if first:
print frame.width
first = False
frame.destroy()
comment: Reading an image from file to img, copying the data to main, and creating sub-images in a sequence seems very memory intensive. I'm sure your doing a lot more than identifying the image width, but can that be rewritten? Imagemagick does have a ping method ( not yet implemented in wand ) which doesn't read image data into memory.