Image Gallery – Click Button to Show Image

I’m working on an Image Gallery with buttons to show images with an [X] in the upper right corner to close the image. While the image is displayed the screen will not be darkened, but will be frozen from clicking anything except for the [X] to close the image. In the attached code there’s a call to a CustomFunction, which is where I really need help. All of the images will be smaller that 500 x 500 pixels and will be displayed in the center of the screen. I’m hoping there’s a way to use…

Image Gallery – Click Button to Show Image