Loading sets of images into arrays using Resources subfolders and string.Format

Hello,

Basically what I have working now is a set of images in the Resources folder, named "frame0001", "frame0002" and so on. This I can load into a Texture2D array with no problem using the syntax:

 for (int i = 0; i < numberOfFrames; ++i)            
         frames[i] = (Texture2D) Resources.Load(string.Format("frame{0:d4}", i + 1));

What I want to do, is to make a couple of subfolders in the Resources folder, say Panel_1 and Panel_2, put sets of images in each, and load them into the array selectively. I can't get the syntax to work however, needing to specify both a path and string.Format in the argument. I'm thinking something like this:

 if (panelWanted == "Panel_1")
             for (int i = 0; i < numberOfFrames; ++i)            
                 frames[i] = (Texture2D)Resources.Load("Panel_1" + string.Format("frame{0:d4}", i + 1));               
 else if (panelWanted == "Panel_2")
             for (int i = 0; i < numberOfFrames; ++i)
                 frames[i] = (Texture2D)Resources.Load("Panel_2" + string.Format("frame{0:d4}", i + 1));

I also tried using Resources.LoadAll in various shape and forms such as:

 frames = (Texture2D)Resources.LoadAll("Panel_2");

but I keep getting errors like:

Cannot convert type UnityEngine.Object[]' to UnityEngine.Texture2D'

I'm sure there's an easy solution but I just can't figure out the correct syntax. Any help is appreciated.