Competition
Before designing an image gallery the owner needs to be aware of the competition that is out there. There are many different types of these sites that are already available to use. The owner of a new one should decide what will make their own gallery service stand out from the rest.
A useful way of doing this is to look at the numerous companies that specialise in this area. This will help to recognise any gaps in the market. Taking inspiration from these competitors is useful but the site also needs to stand out and be 
different.
Researching online image galleries that have failed in the past is also worth doing. This will help a person to recognise the mistakes that were made by these companies. Knowing this will prevent someone from falling into a similar trap.
It is never a good idea to imitate a more successful site too closely. This will just mean that the new site will always be second best. The ideal strategy is to come up with truly innovative ideas. If a gallery site can improve the overall user experience and give them something new then it will stand out from the competition.