Many effects and all cropping of your images can be done directly on your pages. Effects and cropping are non-destructive to your images, meaning that any changes are applied to the frame containing the image, and not the photo itself. You cannot overwrite or make changes that cannot be undone to your source images in the software.
Should you need to make a fine detail edit to a photo already in a layout, you can send it directly to your photo editor of choice.
To send an image to your external photo editing software, first, select the image. Click on the image's menu icon, and choose Edit in External application.
If you haven't already used this option, you will be prompted to select your eternal editor of choice - choose Yes to the prompt. The User Preferences window will appear. Click on the ... button to open your file manager.
Navigate to your the folder containing your photo editing software then the file used to launch that software. For example, on a Windows computer, look for the Photoshop.exe file in C:/Program Files (x86)/Adobe/Adobe Photoshop. On a Mac, you will look for the Photoshop.app file in your App folder.
Once you've specified the file used to launch your image editing software, apply your setup changes. The selected image will now launch in your external editor. Save the changes to your file in your editor - it will automatically update in your project.
Should you need to change your default editor choice, you can do so under the General options. Choose User Preferences then Advanced to access your photo editor path to edit it.