PNG images appear too dark or too light
PNG images appear too dark when imported via Insert, Picture, From File into PowerPoint.
Some versions of Photoshop create PNG images with bad gamma data. There's more background information and several possible fixes outlined in this Microsoft knowledgebase article
- If you have the original image and Photoshop 5, save the image as a different file type (BMP, for example) or change File, Color Settings, RGB Setup, Gamma to half the value that's currently shown and resave the image.
- If you don't have the original image and Photoshop 5, select the image in PowerPoint and use the More Brightness/Less Brightness buttons on the Picture toolbar to adjust the image.
You can also use Glenn Randers-Pehrson's freeware PNGCrush program to repair this and several other potential problems with PNG files.
This problem was originally reported as affecting PowerPoint 2000 and images saved from PhotoShop 5 but may apply to other versions as well.
It's caused when the program that creates the PNG image sets gamma data incorrectly.