Creating a mosaic (?)

[BlakeHoughton]

I have multiple .tif rasters that I need to compile into one raster to preserve the relationship between the images. Whenever I try to use the mosaic or mosaic to new raster, with the intent of exporting all of this into AutoCAD as a .png or .jpg, I either get an error in that the process failed or the backgrounds get pulled along and black squares cover up significant portions of the imagery. Though I have a graduate level intro course to GIS under my belt and I have been working as the acting GIS analyst for a landscape architecture firm, the workflow for this is escaping me and I've put too many hours into this process already. Help me GIS wizards, you're my only hope.

[JustinJohnston]

I think the problem is that the default is for no data to be masked as black for .PNG and .JPG.  You might be able to edit the raster in Adobe Photoshop or another image editing software and delete the black and save as a PNG that specifically has no data set to transparent.  Alternatively, can you export as a TIF?  That might preserve the no data as transparent, but that is a complete guess.