Image Optimization is a fun game, trying to get just the right compression ratio to balance file size and appearance. There are a ton of tricks out there, but as a Photoshop user you generally end up with some pretty big files that are just small images. Today I had an icon, 71x30px that was 40.1kb after I resized it from a larger jpeg that was 38kb.
Where does all this extra data come from? Metadata. Cameras throw it in, flickr reads it and shows the setting your Cannon used to get that photo. Photoshop throws some junk in too. The real evil is thumbnails, Cat Schwartz had a bit of a scandal 6 years ago with thumbnails of un-cropped photos in the metadata that were, shall we say, not suitable for work. These thumbnails can almost DOUBLE your file size. It’s just part and parcel of EXIF (the Exchangeable Image File format) standard, a bunch of useful data that takes up a bunch of space, and isn’t important to the end user.
How do you get rid of EXIF? On OSX you could use Image Optim, which is totally sweet, if you own a mac. On a PC you run into a bunch of poorly written, virus laden, scam-ware programs that may or may not work. Fortunately for us, there’s an Open Source community. So we’ll do this with some FOSS.
- Create a folder for all your image files (which you should do anyhow)
download JHEAD to that folder (jhead.exe main page)
- Create .BAT file (plain text renamed to .BAT) containing
jhead.exe -purejpg *i
- Run it.
What this does is strip out any EXIF and other metadata in the files in that folder. Just does away with anything that isn’t purely essential for a jpeg to be an image, thus saving quite a bit on file size, bandwidth, and hopefully some embarrassment.