I am beginner (so please be patient with me).
I have like 10000 users of which i have physical images stored in a directory as <USERID>.jpg. How do i show this on a form and how do i do this in a grid?
You can create a field of type image and apply the url to it. Also you can make a label field and apply the image link to it. If you need to manage your images then you could create a database with a filename field and initially fill this with all the images. On your form you make a field of type database/file. Be aware that when you deploy you need to choose the advanced option, then you will be able to apply the correct directory on your production server.