Images that appear corrupted, image files that won't import
Image file formats get modified from time to time. Usually this is is an improvement or it adds new capabilities, but it also makes it VERY difficult (can you say "impossible"?) to write image import filters that handle all possibilities. And even if you could write them, they'd be out of date in months, because some new variant of the file format would come along.
Typically, filters for importing files like TIFF into programs like PowerPoint are a generation behind the most current version files produced by leading image editing apps like PhotoShop. That can lead to problems, like the ones we've run into on the PowerPoint newsgroup:
- PNGs from Photoshop 5 can display incorrectly or cause import problems. There's more info and a utility program to fix the problem here.
- TIFFs that use ZIP or JPG compression (introduced in Photoshop 6) rather than LZW or No compression either won't import at all or import badly.
- CMYK TIFFs can produce problems in some versions of PPT
- JPGs with embedded ICC Profiles from Photoshop 5.0 and 5.5 tended to turn into yellow goo
- Some JPGs become "posterized" or "negative-looking" in PowerPoint 2002, while the same file looks OK in earlier versions of PowerPoint.
Fix: Re-open the TIFF, save it with LZW or NO compression, or save as PNG instead.
Fix: PowerPoint will convert ALL images other than EPS to RGB. It's better to do the conversion yourself in your image editing app, then the RGB version to PNG, JPG or TIF.
Fix: Don't embed ICC profiles or embed them from Photoshop 6, which seems to have solved the problem