Available disk space decreasing and increasing randomly

[sparks2303]

I've looked at some of the threads with a similar problem, but I only found questions about space decreasing. Mine increases as well, after no action from me, with no files left in trash.

When the space decreases, it usually settles around 2-3gb, and when it increases it never goes back up to where it should be. When I restart the computer the number looks accurate (around 10gb at the moment), but it never stays like that for long.
I've only noticed this problem a couple of days ago, at a time when no applications were downloaded or removed.
I ran a disk check and it came out fine, virus check also.

Anyone have any idea what it could be?
Please and thank you!

Edit: I should add that I have been using Photoshop during this time, and when I did close the program the space increased significantly. However, the number was acting up still while the program was closed (PS wasn't open the whole time I was on the computer).

 

[GGJstudios]

Temporary work space may be freed up when closing apps or documents. Also, if you're paging and your memory demands decrease, some swapfile space may be freed up.

If you're wondering what "Other" category in the Lion storage tab is about, this may help explain:

What is this "Other" in the storage tab? What is eating my space​

For space issues not explained by the above, there are a few things you can try, some of which may or may not apply:

• Begin by restarting your computer as a first step. This sometimes resolves issues.
  
  
• For Time Machine users on notebooks running Lion, space may being consumed by Time Machine local snapshots, which can be disabled.
  OS X Lion: About Time Machine's "local snapshots" on portable Macs
  
  
• Check to see if some of the space is being used by your sleepimage file.
  
  
• Search with Finder to see if the space is being consumed by a very large file or several large files. Adjust the 50GB in the illustration to whatever size you deem appropriate.
  
  
• Use OmniDiskSweeper, JDisk Report, Disk Inventory X, DaisyDisk or GrandPerspective to see how space is being used on your drive. Some of these apps may show more detail than others, so try several.
  
  
• Check your drive with Disk Utility: Using Disk Utility to verify or repair disks
  
  
• Try re-indexing your drive: Spotlight: How to re-index folders or volumes

Here are a few resolutions found by others with the same question:

• Encrypted drive
• Time Machine backup files and needed disk repair
• App filling log file
• App or file was 89GB
• Drive needed to be re-indexed
• Time Machine backup file
• Large app cache file
• Garageband files and video podcasts
• Oversized email being duplicated
• Another email issue

 

[sparks2303]

That was very helpful, thank you!!