Photobucket has been the easiest to use for me. Here are some helpful instructions so that you can store your banners and any other images.
Register for a Photobucket Account To get started on Photobucket, you'll need to open an account. Don't worry, they're free and easy!
Go to photobucket.com. Make sure that your browser accepts cookies from the site.
Click on the "Join Now" button in the upper right of the home page.
Select a username and password and click on "Next Step."
Fill in the requested personal information.
That's it! Your account is active! From now on, whenever you go to photobucket.com, you can click on "My Album" to go directly to your album.
Upload From Your PC
Select the "Albums & Upload" tab on your main account page.
Select "Images from my PC."
Click the "Browse" button and find the image on your computer. (If you have a lot of images to upload, you might consider using the bulk uploader, below.)
Add a title to your image. If you don't do it now, you can still title your image later on.
Repeat this process for every image you want to upload. Click on the "add more" link if you have more than three images to upload.
Once you're done selecting all your images, click on the "Upload" button. It may take a while to upload your images, depending on how big they are; be patient!
You can now add titles, descriptions, or tags to your images. Again, if you don't do it now, you can do it later.
Finally, select "Save and Continue." Your images have been uploaded!
Use the Bulk Uploader If you want to upload a lot of images from your PC (like a whole folder full of your vacation photos), you may find it easier to use Photobucket's bulk uploader.
First, you'll have to create a folder in your Photobucket account (see below) and be in that folder.
Click on the "Use Our Bulk Uploader" button. This will bring up a screen with multiple windows.
In the "Choose a Folder" window, you can browse on your PC to select the folder that contains the images you want to upload. The images in that folder will appear in the "Click to Select Photos" window.
Click on whatever photos you want to upload, or choose "select all." The selected photos will appear in the third window.
You can add descriptions and titles to individual images if you want, or do it later.
You can choose different folders (going back to the first window) and images and you can delete photos from your upload batch by clicking on the red minus sign next to them.
When you're ready, click on "Upload" to upload all your photos. Again, this may take a while, so be patient.
You can now add titles, descriptions, or tags to your images. Again, if you don't do it now, you can do it later.
Finally, select "Save and Continue." Your images have been uploaded!
It's much simpler than it looks. Broken down it is:
Sign up
Upload images
Use the IMG code on the site.
That's about it