Various websites, including the American Cancer Society, WebMD and Mayo Clinic have photos of skin cancer tumors for the public to view. While these photos aren't meant to provide a medical diagnosis, they are a good basis for users to determine if a mark or bump on the skin should be evaluated by a doctor at an upcoming appointment or on an emergency basis.
Basal cell tumors are the most common form of skin cancer, notes the American Cancer Society. This type of skin cancer accounts for 8 out of 10 skin cancers. It is usually raised and has abnormal blood vessels. The tumor can be dark red, pale red or pink.