The difference between these branding options is where it is displayed in the interface. You may apply your own pictures or use the default settings. Below you may find more details on how it looks.
Login to the data room
By following a direct link to the data room, at the login stage, the user will see the login page background.
If it was not applied, the default one is displayed:
Projects dashboard
Upon logging in to the iDeals account (not directly to the data room), the user will see the dashboard of all the projects he's participating in. So if you upload the dashboard image, it will be shown here.
VDR & Corporate logo
When working in the project, company's logo is displayed in the top-left corner.
Note that the logo will also be displayed on the dashboard, in case the dashboard image was not applied in the settings:
Supported file formats: JPEG | JPG | PNG.
Minimum resolution of the login page background: 1280x1024px.
All available branding options are described in the Branding your data room article.