The best practice is to determine whether there is a genuine dispute over the authenticity of the documents and photographs during the discovery stage. Most jurisdictions provide for a discovery device called "Requests for Admissions" which are well suited for this purpose. If the other party admits to the genuineness of the documents and pictures, you are set to proceed at trial.
If you are unable to do this, you will need to lay a proper "foundation" for the authenticity of the documents at trial. Foundation is simply a legal term for establishing initial evidence suggesting the reliability of the evidence. You will want to consult with an experienced trial attorney to address the adequacy of your evidence and to prepare for your trial.
If you represent yourself, you are proceeding at your own peril. In most states, you will be held to the same standards as licensed attorneys.
Whether unconfined dogs are common to your community may be irrelevant; if you're being cited for something that's a violation of the law, then proof of what is a common occurrence isn't going to help you get around what you may be permitted to do under the laws of your jurisdiction.
In introducing evidence, you have to consider things like...relevancy, hearsay, authentication. In law school there are whole courses on evidence. Accordingly, it's difficult to answer your question because I'm not sure exactly what you're trying to do.
I'd consult with an attorney.
In order to sucessfully move pictures into evidence they must be relevant and you must authenticate them. To authenticate a photograph, you must have a witness on the stand who can testify that each picture portrays what it proports to portray, ie. that it fairly depicts the subject matter when the picture was taken. The witness need not be the person who took the picture, but may be that person. The witness should be able to identify the location depicted and the timeframe during which the picture was taken. Once authenticated and deemed relevant the picture should come into evidence unless it depicts something that is in admissible, prejudicial or is misleading because of angle, lighting or some other issue which makes it an unfair or inaccurate.