Use the IMS server megisims.state.me.us to look at orthophotos or other data for large areas that would be time consuming to download. IMS servers provide just the data that you need at the resolution that you are viewing the map at. One warning with IMS servers is that large maps using IMS server data do not always print correctly
To add data from the Maine GIS servers open ArcCatalog, click GIS servers, then add IMS server
Add megisims.state.me.us
Once you have added the server, open ArcMap and drag and drop the layers from the server you need into the layers frame
See Adding Layers if you need any additional help with this