Hello tita,
I am not aware of any issues on the site that would cause difficulty moving images into an image folder, so it is unclear what may be occurring for you.
I suggest that you first clear the cache of your browser and then log back in to your account to see if the behavior changes. Should it persist, please file a support case from under the Help tab of the site letting us know the details of what you run into. Please be sure that you include the specific steps you are taking when you run into trouble as well as your browser and operating system information and we'll be happy to take a look.
- Craig