Hello Carmen, there could be some possibilities for why this happens, so let's tackle them:

• when you open the Spine project, is the images folder empty? (if yes, maybe the images generator is the problem)
  if no:
• Do you have quite a lot of images?
  A solution could be to disable limit scanning Editor not loading all the images
  if this doesn't solve it:
• Are you using images scattered across your pc or are they in an images folder, enclosed in the folder of your project? And are you using absolute paths (paths that start with C://... etc.) or relative to the project position? (something like ./images/ is what you'd want to have)
  Even when disabling limit scanning, if the images are to be searched in a bigger folder, this could slow down Spine greatly, this is why enclosing the project in its own folder would be best.
  Please let me know if one of these helped or if the problem is elsewhere!