Are there drawbacks to working with layers? Yes, there are several, which may or may not be of significance to the artist.
One major drawback is that many image editing applications that are not the highest-end applications will not recognize an image with layers. Most artists I know do not possess high-end image editing software, but instead use more convenient and less expensive applications. Most of these applications simply cannot open an image with layers, so the image is useless to the artist.
Another drawback is file size. Adding layers to an image can double, triple or even quadruple the file size, or more. Thus an image that began at 50 megabytes might end up as 250 megabytes once it has several layers. Again, it is not uncommon for every-day image-handling software to simply choke on images this big. And there is the storage issue. With file sizes this large you can often only get a couple of them on a single CD, and they begin to fill up a hard drive very quickly too.
It is also true that one only needs images with layers if one intends to edit the image. Once editing is done, there is no reason to retain the layers, except for future editing purposes.
Those of you who have worked with me in the past have seen that I always give my clients three versions of their image, a high-res master tiff, a high-res jpeg version, and a low-res email-sized jpeg version. None of these images include layers, for the very reasons stated above. This way I guarantee that my clients will be able to open their images on whatever platform they are using, and that the images will be of a manageable size.
But didn’t I say that I produce my jewelry images using layers? I did indeed. So what happened to them? On the one hand, nothing. I personally retain and archive the master versions of the images I produce for my artists, with the layers, in case the artist should want to re-edit an image in the future. However, for the image files I give to my clients I usually “flatten” the images.
Flattening more or less collapses the layers, one on top of the other, so that the image becomes a standard, single-layer image again, that any application can open, and that is of a manageable size. This way the artist who works with me gets all of the benefits of images produced using layers, but without any of the drawbacks. And for those artists who are familiar with layers and have the skills to work with them, I am more than happy to provide copies of their images including the layers.
Takeaway: Working with layers during the original image creation and editing process can result in the best possible image, especially if the photographer allows for the editing process and the final background in the original photography. While it is possible to place a piece of art on different backgrounds, it is generally not possible to photograph a piece of art in such a way that it will be able to be placed on any possible background in a way that will be believable and not reflect badly on the artwork.
Images with layers are much larger than images without them, and can be impossible to open in some image-handling software. The best workflow is to judiciously use layers in the original photography and image editing to create the best possible images, archive those layered images for future editing, and also create flattened images which are easily opened and used by most image-handling software.