Very often clients have photos or images that they would like to use for various projects. They always ask if they can use a photo they took or an image they found online. The answer to that question is always hard to explain for some designers. There are two different types of images either raster(also called bitmap) or vector. The type of artwork you can use depends on the project at hand. Vector art is artwork created in programs like Adobe Illustrator or Coreldraw or similar software, where each element in the image are created using a series of straight or curved lines and points. Vector art is based off of mathematical calculations where one point is located in reference to another point. Bitmap or raster images are made up of pixels. Raster images are usually photos of objects or other artwork. The more pixels per inch in a photo the more clear that image is. That is referred to as a high resolution image. Therefore, if you have a high resolution image you can enlarge it without as much “pixilation” or blurriness. So to answer the question on what type of image you can use, vector art always works best across any platform. That is because you can use vector images on websites, where the images can be very small, and on banners and billboards where the artwork can be displayed very large. Chances are very good that if you pulled an image off of the internet, not only is it probably illegal to use, it is a very low resolution image. So, it will look very bad once you enlarge it, even a little bit. Here is a great article that further explains this concept in detail.