The Preview tool on Mac OS X adds transparency during resize!
Steps to reproduce:
Save the following image. It doesn't contain transparent colors and color profiles.
Open it in Finder by double click.
- Resize it to 144 pixels using opened Preview tool.
You will get transparent image. You can check transparency on Photoshop. You will see the following result:
Why does this happen? Only some colors raise the issue.
It look like Photoshop shows transparency on the file without it. So, it's Photoshop issue. As it work very wrong if you select "don't control color profiles" during file opening.