In the late 19th to mid 20th century, the United States Department of Agriculture hired dozens of artists to paint watercolors of every fruit that gro

Rotation-Based Compression

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2024-09-24 20:30:07

In the late 19th to mid 20th century, the United States Department of Agriculture hired dozens of artists to paint watercolors of every fruit that grows in the United States. The collection contains 7,497 watercolor paintings, 87 line drawings, and 79 wax models created by approximately 21 artists. I thought this would make a great set of images to choose a random photo every day to use as my desktop wallpaper. The entire collection is 59.06 GB in size because the images are stored in archival quality.

After rotating the image, I noticed something interesting. The original image’s file size was 12.67 MB, but the rotated image’s size was only 5.41 MB. That’s a huge size saving! And even better, I can’t visually tell the difference.

Clearly there’s a difference that I don’t notice visually. This got me wondering what’s going on when Preview rotates an image. I looked up how Preview rotates images and came across a MacOS tool called sips.

Next, I wondered what would happen if I used a more mainline tool to compress the image to 93%. Surely ImageMagick will be the most efficient right?