Photoshop has a lot of windows, but you only need to learn three of them to start.
Articles > Photography > Name Your Images, Find Your Images
Starting off with a good naming scheme will help you keep track of your images various variations. Here's what I do:
Digital cameras tend to always use the same prifix (IMG_), so its difficult to know where a picture came from. The first thing that I do after downloading the pictures from the camera is rename them to have a new three-letter-prefix that identifies the photographer (i.e., IMG_2318.JPG becomes MSG_2318.JPG because my name is Michael Severin Gobbi). I make sure that my camera is programmed not to reset the image numbers, so I will be able to take 9999 photos before I need to be concerned about duplicated file names.1 You can do this batch rename most easily using Adobe Bridge or your preferred image librarian. Whether you also renumber the photos to close up the gaps (where you deleted pictures) is up to you, but if you are going to do it do it now before you start working with your photos.
I want to be able to match up the raw image with the photoshopped version several months from now. So my first rule of image naming is never change the base name of an image file. Good image librarians let you give your photos titles without renaming the file, and you should always be using a digital librarian to find your old images — it's far faster than using Finder or Windows Explorer. And by keeping the base name the same you will be able to find related pictures easily because their numbers will be similar ("That's a great picture of Jim — didn't we also photograph the Jeep that week?").
If I am creating a multi-image collage in Adobe Photoshop the previous rule obviously doesn't work. In that case I name the Photoshop file whatever I want and I give each layer the name of its source image. In fact, even if I am sticking to just one image I will often have stacked layers & layer effects, so I name my layers appropriately and go ahead and name the Photoshop file whatever I want.
I noticed that digital cameras and scanners nearly always use uppercase for file name extensions (i.e. IMG_001.JPG). So let's use that as another rule: uppercase extensions are used for raw capture and lowercase extensions are used for files that I have edited. This is particularly important for JPEG files, since every time you open and save them the image quality goes down (it's like making a copy of a copy). So with this naming convention I will know never to open and edit a file that ends in .jpg, but .JPG files are fair game.2
Speaking of JPG files, I will often have resave a file with different sizes. I add the size as a trailer to the name (i.e., MSG_2318_480x640.jpg).
So how does this all work in practice?
If the web designer ever wants to get the original photo (maybe I cropped something out that she needs) she tells me she needs the source for JimCurry01_480x640.jpg. I can easily find the Photoshop file, and taking a look inside tells me that the image in question is MSG_2318.JPG.
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