Fix .png files not appearing if Multimedia add-on is installed

Author: RocketRobz

romsel_aktheme/arm9/source/main.cpp

@@ -1259,7 +1259,7 @@ int akTheme(void) {
 					".png" // Portable Network Graphics
 				};
 
-				for (int i = 0; i < 5; i++) {
+				for (int i = 0; i < 6; i++) {
 					extensionList.emplace_back(extensionListMedia[i]);
 				}
 			}

romsel_dsimenutheme/arm9/source/main.cpp

@@ -1221,7 +1221,7 @@ int dsiMenuTheme(void) {
 				".png" // Portable Network Graphics
 			};
 
-			for (int i = 0; i < 5; i++) {
+			for (int i = 0; i < 6; i++) {
 				extensionList.emplace_back(extensionListMedia[i]);
 			}
 		}

romsel_r4theme/arm9/source/main.cpp

@@ -1416,7 +1416,7 @@ int r4Theme(void) {
 					".png" // Portable Network Graphics
 				};
 
-				for (int i = 0; i < 5; i++) {
+				for (int i = 0; i < 6; i++) {
 					extensionList.emplace_back(extensionListMedia[i]);
 				}
 			}