Wait no longer Cristina. This is a frame I made 2yrs ago, with a photo of my 3 girls in. Meg, Nell and Tess my beloved border collie. I opened the file yesterday, used the selection tool to select the photo, and hit delete. I replaced it with the cluster. To make the background paper, I used the cluster to make a seamless tile. Effects, seamless tiling, settings corner checked, horizontal checked. Again, seamless tiling, settings vertical checked. Then on a separate layer, I flood filled with the foreground colour, move that layer to the bottom. I merged visible, adjust, blur gaussian blur. radius 18. Effects art media effects, brush strokes. File, new, materials palette, pattern, choose the seamless tiling you created, and flood fill. Save.
Open the cluster, new mask layer, from image. Copy and paste the masked cluster onto the background paper. Tip: This is how you get different shades of the same colour. Materials palette, left click into background colour and change the ‘lightness’. (Materials palette, change from wheel to slider. change RGB slider to HSL slider, and change the lightness according to what you want). I make notes as I go along, I hope I haven’t left anything out, and it makes sense to you.