Holdr is going to look for the system screenshots default saved location folder and prompt for user authorization for access. If screenshots folder is changed Holdr will ask again for user authorization for the new location. Previous screenshots will remain in the previous folder, in order to be available in Holdr you need to manually move the screenshot files to the new screenshots default save location folder.
Open Terminal application located in Applications/Utilities/Terminal.
In Terminal type the following:
Now drag and drop your Screenshots folder on top of the Terminal window and it will automatically fill in the directory path and press Enter
For the changes to be applied type the following: