No GIF images used
This check reports when the file format of any placed images is GIF.
GIF, pronounced with a hard G (Graphics Interchange Format) images are a mostly obsolete file format.
Although they can contain transparency they can’t handle partial transparency. Each pixel is either a solid colour or transparent.
GIF cannot display more than 256 colors and cannot be colour managed. For this reason, it is less effective for displaying photographs online (use JPEG instead) and is not recommended for commercial printing. If the image has flat colour or includes type, use the PNG format instead.
Fix this problem by using a more current format of the same image or using an alternative image.
Tip: It is possible to switch on a file types (a.k.a Format) column in the Links Panel. (InDesign Window menu > Links). First choose Panel Options from the Links panel menu.
In the Panel Options dialog under the Show Column heading click the checkbox for Format and click OK.
In the Links panel a new column appears indicating the Format of images. You may need to adjust the widths of the columns or panel itself to see all the information
Adobe Importing File Formats help
