moderated Re: Question about image processing #misc


On Tue, Oct 26, 2021 at 11:22 AM, D R Stinson wrote:
David -
Two possibilities come to mind. Do you have the image size limited to 1024 x 1024 or smaller? Can you convert them to JPG files instead of PNGs?
I suspect the system was designed around common JPGs, and PNGs might be confusing it. If you're using a different palette, that palette may need to be included with the file. You might experiment with that possibility.
I've used one of several draw programs for image compression, but I've found that in many cases Irfanview does a credible job quickly.
Most of the images I use are screenshots. So the only "limit" on image size is my monitor, which is 1920 x 1080 (often "dumbed down" to 1600 x 900 -- I'm old, and my eyesight is failing). I usually take a shot of just a portion of the screen, so my images are rarely any larger than 1024 x 1024.

I played around with GIMP, the GNU Image Manipulation Program ( In general, converting a .png file to .jpg format increases the file size by some 100% to 150%. That's for screenshots. If I were processing photographs, .jpg would most likely be the better choice, in terms of file size. But screen shots of web sites usually contain a lot of straight lines and sharp corners, which are more compactly encoded by the .png algorithm. Oh, yeah. JPG files have been around since 1992. But PNG came along in 1997, and software support for the newer format is fairly ubiquitous. I'm sure Mark uses programs that support a great number of file forrmats. For instance, the aforementioned GIMP (free software) supports 40 different file formats, from als to xwd.
David Bryant
Canyon Lake, Texas

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