You mean like one of these from SanDisk?
It looks like you'll need to manage the images you want to edit in PS Touch with SanDisk's app *before* opening them up in PS Touch. (e.g., You'll need to download an image to your iPad with the SanDisk app before opening it and editing it in PS Touch.)
Thats the problem i can only download psd files but when it asks what to use to open it to view i get none of the adobe programmes to choose i have several installed even lightroom but not one shows up, tried using progs first but they dont see media drive only online from adobe
PS Touch supports import of JPEG, PNG and GIF images on your device; RAW and PSD images from Creative Cloud. Note that PSD images will be flattened when imported. You should have several options as to the source of import, including the Camera Roll.
If I remember correctly, Lightroom Mobile works more or less like an extension of Lightroom for desktop. You basically work on your images that on your desktop through your tablet, never directly.
The workflow would be (if using the SanDisk drive):
Import a JPEG, PNG or GIF image from the drive directly onto your iPad. Then open that image in PS Touch.
If using Creative Cloud, upload your RAW or PSD images to Creative Cloud (using a valid method such as uploading them from your desktop), then import them in PS Touch.
I Can view jpeg, i can view psd with psd viewer by some russian guy as icon appears in list to open file but it only gives me very low bit. So if that software works with ipad why doesnt adobe which is made to view psd file but none show up on list. I cant download files onto ipad to view as no room hence why i bought external storage which works via wifi. No point using cloud storage as camera club does not have wifi
PSD files can be big with potentially hundreds, if not thousands, of layers. Photoshop Touch can only support 12 layers max (for obvious reasons, mostly hardware). It's just the nature of the beast until tablets catch up to their desktop brethren.
I can't speak as to why PS Touch's file management is a bit rigid compared to other apps. (e.g., Autodesk's SketchBook Pro lets me import or save to Dropbox but I think that one's a bit obvious; Dropbox is more or less a competitor to Creative Cloud.)