This is the bathymetry data used in generating the Blue Marble Next Generation w/ Bathymetry imagery.
There is a BIN file included, which is the raw format, and not an image. Reto Stockli has provided the following explanation of the format: .bin files in the BMNG file repository are made of 8bit unsigned binary files, structured as 3 Channels X 86400 columns X 43200 lines. No header data, no ASCII text data in these files. You read the files as a byte array with 3 dimensions: 3x86400x43200 where the first dimension are the RGB (Red Green Blue) color triplets of the image, the second dimension are the number of columns (X dimension) and the third dimension are the number of lines (Y dimension). The image starts with 3 bytes of the RGB values of the northernmost and westernmost pixel. The next 3 values are the RGB values of the one pixel to the east of the first pixel. And so on. Geographic projection with a regular grid spacing of 0.004166667 degrees per pixel.