From the stage they are at in the image you should leave them in those pots for a while. Repot when they grow a few more sets of leaves. It is best to increase the pot size gradually, I do it from a plug plant, to 9cm, to 15cm and then into a 10 litre final pot.
Keep them in well drained compost with plenty of perlite, and dont over-water. Water only when the soil is visibly dry, and feed weekly with Tomato feed or similar.
Most of the domesticated varieties require very little effort for a good crop of peppers.
Good luck.