This tutorial covers making a tileable texture (also called a seamless texture) from a photo inside 3ds Max. No extra plugins are needed. All you need is a photo.

1. Create a Plane primitive. Make its length and width match the dimensions of the bitmap you want to create. For example, if your bitmap is going to be 512x512 pixels, make the plane 512x512 units.
2. Create a new Standard material in the Material Editor.
3. Apply your bitmap to the diffuse slot of your material.
4. Apply this Material to the plane above. Make the material viewable in the viewport.
5. Apply a UVW Map to your Plane object. Choose the Planar UVW type (the default).
6. Enter the Gizmo level of the UVW Map modifier in the modifier stack.
7. Turn on Snapping and choose Vertex Snapping.
8. Snap the center of the gizmo to a corner vertex of the plane.
9. Exit the Gizmo sub-object level.
10. Open the Viewport Canvas (Tools > Viewport Canvas)
11. Choose the Clone tool.
12. Pick points on the object to clone (by alt-clicking those points).
13. Paint the cloned images along the visible seems in the image.
14. Repeat the process until the visible seams are gone.
15. When finished, right-click and save the image.