1) NitroSell Default Image Profile(s): Yes & No. Your suggested deviation from the adopted default image directory in RMS is possible by overriding the directory in your NSc Sync (Server Ed if HQ). However, PAM will not be affected by this change and will continue to reference (Read and Write) the default image path targeted through RMS Admin or RMS HQ Admin respectively. This in not ideal.
2) Image Sizes: The RMS picture preview window is 275w X 175h px. By assigning images larger than that, you will only see that portion of the top left corner of that image. In order to provide your webstore customers with large detailed images, one large image must be available to NSc Sync so that it may size down and create 3 copies of that image, Large, Default and Thumbnail.
Suggested Solution: You likely have multiple RMS machines on your network. On the machine where NSc Sync (Server) and PAM are installed, set RMS Admin or RMS HQ Admin to the larger image directory “\Pictures\img1”. This way Sync, PAM & RMS on that machine will all Read and Write to the larger image folder.
Further, I recommend setting all other machines to the picture folder containing smaller versions of the images “\Pictures” so your in-store staff can see appropriately sized product images.
Image Profiles: Your webstore will support 24 image profiles. Based on your current count, you may add another 3 folders with 3 profiles each.