IMO the overlap method that you’re using for your slideshow is not the best method to use. Before key frames and the additional filters that have been added to Shotcut it was probably the way to go but now there are more options.
An alternate method to the overlap method is to use two tracks.
Put all your images on V2 using the add all to timeline function.
Move every other image to V3.
Overlap the upper image over the lower track images.
Apply opacity filter to the upper image key framing it to start from 0% then go to 100% at the beginning of the clip to fade in. For the end of the clip fade out going from 100% to 0%. You could also use fade in fade out filters instead of opacity. Or you could use the mask from file filter and key frame that.
Once you have the filter set up, simply copy the filters and paste them to each clip.
Key framed opacity filter.
Or you can put all the images on the timeline. Split each clip at the duration you want for the transition. Then move all the split sections to an upper track and position them over the preceding clip. Enable ripple trim and drop to close the spaces. If you want a simple dissolve apply an opacity filter to the split clip and key frame it from 0% to 100% then just copy the filter to all the other clips. You can also use the mask from file filter and key frame it to create wipes.
This requires a bit of work but it’s easier than using the overlap method and you have more flexibility and control over the transitions.
@sauron thank you for help thus far. I’ve currently experiemnting with the second method you mentioned. With this method, I really wished there was keyboard shortcuts for 1) moving selected clip to the above track 2) changing the selected clip 3) keyboard shortcut for pasting filter or a different approach to video track wide filter.
Move the play head to the beginning of the first small clip. Ctrl right arrow to select it. Ctrl-X to cut. Up arrow to move to the upper track. Ctrl-V to paste. Down arrow once. Alt-right arrow once. Ctrl-right arrow to select the next clip. Ctrl-X to cut. Up arrow to move to the upper track. Ctrl-V to paste.
Keep repeating until all the clips are on the upper track. Select the very first small clip. Use the mouse to drag it so it overlaps the first clip. All the clips to the right will be moved left and you’re done.
You should take a look at this page for all the keyboard shortcuts.