Instagrab is a WordPress plugin that grabs images from one or more Instagram hashtags and create a post for each image.
Please don't spam the Instagram API with super many hashtags! Only use 1-5 hashtags, please. Your site is going to be slow and Instagram won't like it.
Because you haven't set the timeout interval in the settings panel. Set it to 30 sec or more.
This will make a lot of problems for you. It will only download new pictures from Instagram when the cache has expired. Sorry! But you are more then welcome to try. If you know what you are doing, you can config the right stuff and you can get the result you want.