I would advise against "displaying the images from the directories in a for loop." What about the following setup?
- Pushbutton #1 (load images): When the user presses this button, they are queried to select a directory of images from file. Those images are all loaded into the GUI and stored in a variable (e.g., I).
- Axes: I assume there is an axes in your GUI to display the images. Use a variable (e.g., current_image) that keeps track of the index of which image to show. When that variable changes (from the Pushbutton #2), use a listener function to update the image that is shown in the axes.
- Pushbutton #2 (change images): When the user presses this button, the variable current_image updates (triggering the update of the image shown in the axes). In fact, if it were me, I would use a slider that ranges from 1 to the number of images so that the user can move forward and backward through the directory of images; in this case, you can simply use the value of the slider instead of current_image.
- Pushbutton #3 (starts imfreehand tool): you don't explicitly say this, but I'd suggest incorporating the imfreehand as a button that the user selects. In this way, the user can decide when they want to draw on the image, instead of being forced in a for loop.
Does this make sense? Let me know if anything is unclear.
