A gallery of STD pictures can't diagnose you, but if you're curious...

Cold sores, or fever blisters, are caused by a herpes virus.

Cold sores are small painful blisters that are most often found around the lips. They usually break open, crust over, and heal over the period of a week to 10 days.

Although many people do not refer to them that way, cold sores are actually oral herpes. They can be transmitted to a partner's mouth through kissing. They can also be transmitted to their genitals during oral sex. Yes, it's true. If you have oral herpes, you can give someone genital herpes by performing unprotected oral sex on them.

An outbreak of genital herpes is characterized by several blisters that break open and become painful sores.

These genital herpes pictures are characteristic of the sores associated with a genital herpes infection. However, not everyone who is infected with genital herpes will have symptoms. In addition, some people will have symptoms without noticing them. That's why it is possible to pass on herpes to your partner without ever realizing that you are infected.

Suppressive therapy may not only reduce symptoms in people with frequent outbreaks, but also make infecting a partner less likely.

Looking at genital herpes pictures may help you determine if you do have herpes. What it won't do is tell you if you are herpes-free. There is no way to be certain that a person does not have herpes unless they have been tested. Many, possibly even most, people who carry the virus do so completely unaware.

HPV is becoming widely known as the virus responsible for cervical, oral, and other cancers, but it can also cause genital warts.

These genital warts pictures give you an idea of what such an infection may look like. The extent of a genital wart infection can vary from person to person. Some people end up covered in genital warts. Other people may only experience a few isolated lesions. In either case, it is important to get such symptoms checked out by a doctor. They can detect any pre-cancerous or cancerous changes that may also be present.

Not everyone who is infected with HPV will have symptoms. There is no way to tell if someone has HPV simply by looking at them.

Although these genital warts pictures will help you be certain that you do have genital warts, there is no good way to be certain that you are not carrying one of the viruses that can cause them. Currently there is no commercial test for HPV in men. Although there is an HPV test for women it is designed to look for the cancer-causing varieties. It does not look for the low-risk viruses that are more likely to lead to warts.

In men, chlamydia and gonorrhea in men often have no symptoms. However, sometimes they present with penis discharge, redness, or swelling.

Urethritis is a swelling of the penile urethra. It can be symptomatic of many sexually transmitted diseases - most commonly gonorrhea and chlamydia.

Men with gonorrhea are more likely to experience discharge than men who are infected with chlamydia. However, a large number of men with either condition still experience no noticeable symptoms. That's why screening is so important. Just because you do not have penis discharge or discomfort does not mean there is no infection.

This STD picture shows what your doctor may see when she examines you if you have a cervical infection such as trichomoniasis, gonorrhea or chlamydia.

It's not uncommon for a woman to be infected with an STD for years without ever realizing it. That's why screening is so important. Screening can detect an asymptomatic infection with gonorrhea, chlamydia, or another common STD. It also can prevent the development of fertility problems such as those caused by pelvic inflammatory disease.

These syphilis pictures show the sore typical of a primary syphilis infection. Chancres are normally round and painless, which can make them difficult to find. That's particularly true if they're deep inside the mouth or the vagina. 

The round, usually painless, sores seen in these syphilis pictures represent the first stage of a syphilis infection. These sores are known as chancres.

Syphilis chancres are reasonably easy to spot on the external genitalia, as you can see in these syphilis pictures. However, there is a growing epidemic of syphilis being spread by oral sex. Because the sores are painless, chancres may go unnoticed or misdiagnosed if they occur in the mouth. As such, orally transmitted syphilis infections are more likely to go undetected and untreated.

A chancre will usually heal on its own in three to six weeks. That does not mean the underlying syphilis infection is gone.

If left untreated, syphilis can lead to systemic health problems and even death. That is why testing is essential if you believe you may have been exposed to syphilis.

These pubic lice pictures show the skin response to a pubic lice infection. These lice cause an itchy rash. People may also see visible lice on their skin. Pubic lice is easily spread through intimate contact. It is not usually spread through shared clothing or sheets. 

Pubic lice are usually found in the genital area, but they can be spread to other coarse body hair. They are not usually found on the head. 

This scabies picture shows what the skin response to a scabies infestation looks like.

One thing that scabies pictures cannot show you is that the rash an infestation causes often becomes much more itchy at night. Scabies symptoms primarily show up on folds of skin. Common areas include between the fingers, on the wrists and ankles, and in the genital area.

As seen in these molloscum contagiosum pictures, the MC virus causes a benign skin rash. 

Molluscum contagiosum is an extremely contagious skin condition. It is most often seen in children. Caused by a pox virus, it can be transmitted sexually as well as through casual contact. People can also spread a molloscum infection from one area of their body to another by scratching or rubbing the molloscum sores.

The sores seen in these molluscum contagiosum pictures are usually not itchy or uncomfortable. The virus causes no lasting health problems. However, if sores are present in the genital area, doctors may recommend treating the molloscum infection to prevent transmission to others.

Scratching molluscum sores can also leave open wounds that may be susceptible to secondary bacterial skin infections. That can be seen in this picture of a patient with molloscum contagiosum.

Chancroid is a bacterial STD rarely seen in the United States. This chancroid picture shows a lesion characteristic of early chancroid.

Like syphilis, chancroid is considered to be a genital ulcer disease. Infection with chancroid increases a person's risk of acquiring HIV.

Chancroid is a bacterial STD rarely seen in the United States. This picture shows a burst inguinal lymph node. The inguinal lymph notes are located near the  hip crease and drain from the buttocks, legs, and groin. 

Swelling of the lymph nodes of the groin is a common symptom of chancroid. However, the infection will not always progress to a state where lymph nodes burst or experience other external drainage.

Worldwide, trachoma is the leading cause of preventable blindness. It is caused by a chlamydia infection of the eye.

These chlamydia pictures show the blindness that is one of the potential long-term consequences of a chlamydia infection. Genital chlamydia infection will not cause blindness -- only infection of the eye itself can do so.

Blindness caused by chlamydia is rare in the U.S.. Doctors routinely treat newborn infant's eyes to prevent such infections.

Ocular chlamydia infection is usually transmitted during birth. It can also be transmitted by touching infected secretions and then touching the eye. Gonorrhea can also cause ocular disease.

Canker sores, or aphthous ulcers, are usually round white sores with a red border. They generally heal within 1-3 weeks.

Canker sores, unlike the similar-sounding syphilis chancre, are not STDs. In fact, they are not contagious at all. Instead, they are linked to various nutritional deficiencies as well as certain immune problems.

The yellowish tinge associated with jaundice is caused by a buildup of bilirubin in the blood.

Jaundice can be a complication of the liver damage caused by hepatitis. The yellowing of the eyes and skin seen here is characteristic of the condition, which is also known as icterus.