растры должны иметь файлы привязки tfw, jpw и т.д
чтобы создать такой файл ручками для растра привязанного в ArcGIS см:
http://support.esri.com/index.cfm?fa=knowledgebase.techartic les.articleShow&d=29439
можно скриптом - ищи Create World File from Internal Georeference на:
http://edndoc.esri.com/arcobjects/8.3/ или в ArcGIS Developer Help.
Adding images
You can work with images in ArcExplorer by displaying them as a background layer in your map configuration file.
You can add JPG, TIF, GIF, BMP, and PNG image files to ArcExplorer.
Each image must have a corresponding world file—a file that contains the real-world transformation information used by an image. Generally, world files use the same suffix as the image, with a "w" appended. For example, the world file for the image file mytown.tif would be called mytown.tifw. However, since ArcExplorer does not accept 4 character file extension names, the world files should use the first and third characters of the image file suffix, appended with a "w". The acceptable world file for mytown.tif would be called mytown.tfw.
If a folder contains more than one image, the top entry in the Catalog will be *ImageDirectory. By clicking this choice, you can add all the images in a folder.
You can make an image transparent to view overlapping images in a single map. You can set the transparency value of an image or ImageService in the Layer Properties dialog's General tab.
How to add a single image:
1. Click the Add Layers button to open the Catalog.
2. Click the File Type dropdown and choose Image Files.
3. Navigate to the folder that contains an image.
4. Click an image to add.
5. Click the Add Layers button.
6. Repeat steps 4 and 5 to add more images.
7. Click the Close button to close the Catalog.
How to add an Image Directory in the Catalog:
1. Click the File Type dropdown and choose Image Files.
2. Navigate to the folder that contains more than one image.
3. Click the *ImageDirectory entry in the Catalog.
4. Click the Add Layers button. All the images in that folder are added.
5. Click the Close button to close the Catalog.
