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Outputs the number of different pixels.
2 params to increase tolerance:
* thumbnails size
* fuzz, the color distance tolerance
See http://en.positon.org/post/Compare-/-diff-between-two-images for more details.
Keep width to a power of 2 to see patterns emerge. 512 is good. So is 4096 for huge maps.
PNM headers are super basic.
Compose 2 images (foreground.jpg with background.jpg) into 1 (image.jpg), the numeric parameters stablish the size of the foreground.jpg image (96x96) and the position x,y (+250+70) relative to the background.jpg image.
Images can be any format, jpg, png, bmp, etc...
Digital cameras embed EXIF data into the images they create indicating which orientation the photo was taken in. Some viewers and editors are smart enough to read this, but many are not (and web browsers ignore it). jhead is one of not many tools available that can losslessly rotate jpeg images. This command reads the EXIF orientation of each image, and rotates it if necessary.
If your version of curl does not support the --compressed option, use
curl -s http://funnyjunk.com | gunzip
instead of
curl -s --compressed http://funnyjunk.com
So you are in directory with loads of pictures laying around and you need to quickly scan through them all
-d Draw the filename at the top-left of the image
-F fullscreen
-z randomize
-D 1 - delay 1 second between changing slides
This command will show images in subdirectories as well.