undefined function or variable 'basefilename'

Answer 1

[Walter Roberson]

[file, filepath] = uigetfile({'.png'; '.jpg'}, 'select one or more files', 'D:\', 'Multiselect', 'on');
file = cellstr(file);   %uigetfile returns char if user selected only one
FileNames = fullfile(filepath, file);  %no loop needed
fullFileName = FileNames{1};
ImageArray = imread(fullFileName);

Your most immediate problem was the typing mistake of basefilename instead of baseFileName, but you had other problems as well.

Answer 2

[Steven Lord]

The variable basefilename used on line 8 of your code is not the same as the variable baseFileName defined on line 7. Case matters.