Business owners seldom care to learn a great deal about graphic design, but understanding the value and meaning of owning layered, original source and vector graphics will save money, time and help you keep your artwork reconsistent. The reasons for keeping artwork, like logos, consistent is a much longer conversation about brand impressions. It's expensive and time consuming to reproduce artwork or hack on old artwork that isn't saved in a format that allows incremental modification for a new ad piece or website update. Requiring your artist to provide you with the layered and original formats of all your artwork will save you time and money, as well as help you produce a more consistent look and feel on all your marketing materials.
Below is an example of a layered original source Photoshop file. It would have been nice to also have the individual gaphics used to create this image in their original format. But, just having the layers to manipulate saves a lot of time. In Photoshop the new artist can easily maniulate a few things and pull the elements we need to make the new website.

By simply turning off certain layers, the new artist can create graphics that are required for the new site design, without having to tediously shade out unwanted graphics or degrade the desired portions of the image. Without the layers, taking the picture of the man in this image as a single layer for the website would be virtually impossible. We would lose some details in the original image if we just blacked out the unwanted text.

In mere seconds, by just turning off a few layers, we have the original background photo with the desired shading effects. We do not have to go back to the original photograph and recreate the effects we liked from the original graphics in order to produce an unmolested background photo, less the unwatned text.

We can grab elements of the complete image singly for other purposes. Here we select a single layer that contains the wanted graphic for the bottom right corner of the website. Now we can slice it out and use a clean version with the proper colors for this site. In this case, the prior artist didn't include the layered original graphic for this logo. However, making color changes is simpler because we do have a clean layer from which to work. This is an example of how having all the original work can be useful. There is, no doubt, an original graphic where we can manipulate texture, size and shapes to modify the graphic if we wanted to change the original logo to something new.
Below we have a graphic provided by a different client. He converted the file to a Photoshop file from his original Corel Draw image. But, it is not editable. There is a graphic, gradients and a photo in this image. Editing this image will require the new artist to recreate it from scratch or degrade the quality of the image. This image is no more useful than the jpeg from the website. There are no doubt many layers and effects involved in this design. For example, if we want a different picture of the man's face on the right side, or wanted to change the colors in the gradient blue line, it would be much easier with a layered graphic like the one from the prior project.

