I try to understand the practical difference between using different quality values when writing to PNG.

I have a PNG image (a screenshot of a web page) around 1000 by 9000 pixels, and I want to slice it into a multipage PDF, either Letter (8.5 by 11 inches) or A4 (210 x 297 mm), with 1 inch margins.

To create a PDF, it is often suggested to use -quality 100:

The ImageMagick website suggests to accomply -rotate with -trim:

I. I don’t understand how to specify image’s orientation.

I have a image with gif format like following:

To trim image’s whitespace, I use

 I need to composite a soft light layer on top of a base image using 50% opacity. The following works, but is there a faster or more efficient way to achieve the same thing?

I was looking for how to get the image’s (JPEG, PNG, TIFF) PPI value and all the solutions I found look something like this:

I was looking for how to get the image’s (JPEG, PNG, TIFF) PPI value and all the solutions I found look something like this: