As an FYI, I ended up sharing individual raster feature classes by right clicking in the TOC>Sharing>Share as Web Layer. I selected Tile, then went to the configuration tab and change the level of detail using the little scroll bar thing. When that was shared and cached, I was then able to add each one individually to my web map. Unfortunately, if you try to share as a web map from the share tab, you will not be able to get the layer to be visible at levels zoomed in beyond the 1:1,250. I suspect that the purpose for ArcGIS Online to do this is likely the fact that it takes a bunch of tiles to get that to work. It is definitely burning the credits in ArcGIS Online much faster than in the past. I suppose the extra steps make that more difficult to add data heavy content. My little 5 acre site is now burning 18 credits a day in ArcGIS Online.
Cheers,
Justin