User:Dbenbenn/Image tutorial

Here are some technical details that I've learned in the last few months.

Slogans
 * Higher resolution is always better.
 * Repeated lossy compression is evil.
 * Always keep the original.

Digital camera

 * Set your digital camera to the highest resolution possible.
 * Set the JPEG compression to the highest quality possible.

Cropping

 * Always upload the original, uncropped image first. Someone else might want to crop it differently.
 * Don't use Photoshop or the Gimp to crop a JPEG file. The remaining part of the image will lose quality.  Instead, use jpegtran, which can do various lossless transformations.

Other

 * Use pnmpsnr to verify that two images are identical, for example when converting TIFF to PNG.
 * Use pngcrush to losslessly reduce the size of a PNG file.
 * Use pnmcrop to crop a diagram to its bounding box.
 * Choose a good name for your image.
 * Avoid CamelCase.
 * For an artwork, use the title.
 * Otherwise, use something descriptive.