Synthesis Image Support

You can get Synthesis Image Support from two NPCs in your Guild. One of them will boost your skill by one level for a period of a few minutes. The other one will boost your skill by two levels for a period of a few minutes.

To get the support, just talk to the NPC and accept the Synthesis Image Suppert they offer. It will be free.

See the Guild you want support from to find the NPC that gives it: Crafts