Every time anyone uses the image search command, X-Bot asks Google to provide some results. In return, Google asks for an API key, which uniquely identifies X-Bot.
If at any point, X-Bot asks for more than 100 times per day, Google stops responding until I feed it more money. Unfortunately, my wallet is not bottomless, and we all will have to do with 100 requests/day.
That means that across ALL of the servers X-Bot is in, the image search command can only be used 100 times daily.

Obviously, not every server wants to share its limit with the rest, and you can easily have your own 100 searches/day limit!
To make it happen, all you will need is a Google account! Just proceed to Google's Developer Page and click on "GET A KEY" button at the bottom.
Congratulations, you now have your own API key! Google provides a free limit, and unless you explicitly tell it to, will not attempt to charge you or go above that limit.
Now, all you have to do, is tell X-Bot to use that key instead of default one, to do so, just type "x.api_key INSERTYOURKEYHERE" anywhere on your server where X-Bot can see it. This is it!
ATTENTION! DO NOT SHARE THAT KEY WITH ANYONE UNLESS YOU WANT PEOPLE TO USE YOUR LIMITS/POTENTIALLY GET YOU BANNED FOR INCORRECT USE OF THE API!

100 searches per day isn't enough for you? Well, going to developers dashboard and connecting your credit cards, as well as allowing for the image search to go above 100 requests can allow you to search more!
However, I shall not provide more details on this page, please, use Google.com or other resources. As well, for the purposes of managing your budget, 1 search command = 1 request, no matter of its results or if it is the same query. I am not responsible for how the server will use your API key to search for anime pics!