问题已解决

1.通过对所有图像和文件使用.tif扩展名修复了无法识别的参数
1.(附加不起作用)通过在循环内使用spintf(‘%d.tif’，k)；对每个图像使用不同的名称，如1.tif，2.tif，...
代码：

for k = 1:10
  % read the images from one file  
  jpgFilename = sprintf('%d.pgm', k);
  fullFileName = fullfile("filename", jpgFilename);
  if exist(fullFileName, 'file')
    imageData = imread(fullFileName );
  else
    warningMessage = sprintf('Warning: image file does not exist:\n%s', fullFileName);
    uiwait(warndlg(warningMessage));
  end
% then ,I did some process in the image 
% after process , save the image 
% find the file path to save the image inside it 
folderCover="/Users/myName/Documents/MATLAB/Cover.tif"
% make name for every image -> 1.tif , 2.tif , 3.tif , ...
jpgFilename = sprintf('%d.tif', k);
 fullFileNameCover = fullfile(folderCover, jpgFilename);
if k ==1  % first time to write 
imwrite(imageData,fullFileNameCover );
else 
imwrite(imageData,fullFileNameCover,'WriteMode','append')
end
end