Try this code snippet. The below code will read images, whose locations are specified in the testingdata.txt file and will also label them according to their foldernames.
% Read the filenames and put them in cell array
fId = fopen('testingdata.txt');
tline = fgetl(fId);
tlines = cell(0, 1);
while ischar(tline)
tlines{end+1, 1} = (tline);
tline = fgetl(fId);
end
% Create an imageDatastore object
imds = imageDatastore(tlines, 'LabelSource', 'foldernames');
