When I managed a prepress scanning department that handled thousands of images, I used a simple naming convention that anyone (even creatives) can use which practically made the images organize themselves - and avoided incorrectly formatted images from being placed into page layouts or used for the wrong application.
The naming convention followed this coding format:where the first letter of the image mode and the first letter of how the image was purposed are used as the first two letters of the image name. By naming image files this way, whenever a folder containing images is viewed by name, the images will be automatically grouped according to their mode which makes choosing the correct image format very simple.
It also used a descriptive name that was logical enough to be searched on. I used a date code in the name so that as the image went through the editing/revision cycle I would save the updated images with the new date in the name. This meant that I had copies of the image that tracked the revisions done to it with the most recent version of the image being the one with the most recent date in its name. This avoided using the ambiguous term "Final," "Final v2," "Latest Final" etc. in the image name.
Image mode codes:
R = RGB
C = CMYK
G = Greyscale
B = Bilevel/Bitmap
M = Monotone
D = Duotone
T = Tritone
I = Indexed
P = Publication/SWOP
S = Sheetfed/GRACoL
N = Newspaper/SNAP
F = Flexo/FIRST
W = Web
D = Display Inkjet
B = Backlit Inkjet
Some examples showing how the codes are used in practice to easily identify/describe the image:
GN_Sydney_Harbor_Australia_201008.tif = Greyscale image purposed for Newspaper reproduction.
RW_Sydney_Harbor_Australia_201008.jpg = RGB image purposed for use on a Web site.
CP_Sydney_Harbor_Australia_201008.tif = CMYK image separated for use in a magazine.
B_Sydney_Harbor_Australia_201008.jpg = Bilevel/Bitmap image.
MF_Sydney_Harbor_Australia_201008.eps = Monotone/single color image prepared for Flexographic printing.
DS_Sydney_Harbor_Australia_201008.eps = Duotone/two color image prepared for Sheetfed printing.
IW_Sydney_Harbor_Australia_201008.gif = Index mode image prepared for posting on a Web site.
In some cases I would add the word "TOSS" to the image name:CP_Sydney_Harbor_Australia_201008_TOSS.jpg = CMYK image prepared for Publication. "TOSS" signified that the image could be trashed/erased if hard drive space was needed.