Using a Web Map Service (WMS) is a great way to easily get up-to-date imagery for your project. An issue you may run into, however, is that a server may not allow you to download images over a certain size (in pixels). The image resolution provided on most servers is usually high enough for most projects but there may be some instances where a higher resolution is needed (e.g. a poster-sized map or a web map that covers a large area).
With the latest release of Geographic Imager 5.2, it's now possible to easily import images directly from an ArcGIS Online account or an ArcGIS web service. This will allow you to use shared data within your ArcGIS Online organizational account and connect to publicly available map servers from various online sources.
When georeferencing a map in Geographic Imager, there are two tools which can be used to check spatial accuracy: Validate and Show Image Extents Online. With Validate, click a point on the image and it will show the corresponding location on the web map service so that you can compare the difference between them. Show Image Extents Online will display a rectangle representing the spatial extent of the image on the web map.
If you launch Adobe Photoshop and then realize that extensions didn't load properly, including Geographic Imager, it may be due to a setting in Adobe Photoshop Preferences. Go to Edit > Preferences > Plug-Ins. Locate the ‘Load Extension Panels’ in the Filter and Extension Panels group. If it is unchecked, it prevents all extension panels from loading and the Window > Extensions menu is greyed out and prevents users from opening extension panels manually. When this preference is checked, the Geographic Imager panel will load on start-up.
Some Adobe Photoshop CS5 and CS6 users may be experiencing a blank panel issue in Geographic Imager, specifically from version 4.0 to 4.4.