BMP is Windows bitmap format, used for graphics. It does not provide coordinate system information. When exporting, .prj and .mapmeta files are written. See the Exporting topic.
By right-clicking into the Import dialog and choosing View we can ask Windows to display the files as Large icons instead of as Details.
Windows will then preview the contents of .bmp files as icons.
To import from BMP format:
Choose File-Import from the main menu.
In the Import dialog browse to the folder containing data of interest.
Double-click the file ending in .bmp for the data of interest.
A table and an image will be created.
We can double-click on images that are created to view them.
This particular image shows a WWI trench map of the region near Ploegsteert Wood in Belgium. It is not georegistered and has no coordinate system assigned. By default, we can assign it a Pseudo Mercator projection, which is meaningless other than to provide a coordinate system for the pixels.
We can choose View - Zoom to Native to see the image at the scale of one pixel in the image to one pixel on screen.
Using graphics files - Images in formats such as BMP that do not provide coordinate system information can be handy as illustrations in layouts or for other purposes. Manifold project files are so efficient that we can keep libraries of many images for fast viewing in Manifold, even if we do not intend to work with them in GIS. We can also use Manifold to convert images between different formats, importing an image as one format and exporting it as another.