Restriction digestion image with EcoT22i for library preparation of GBS. I am not clear weather it is digested or needs further troubleshoot?

Is there a particular reason that you are using EcoT22i? What species are you working with and what is the genome size? EcoT22i is a methylation-sensitive 6-bp cutter. Either the DNA is not digested or EcoT22i cut so infrequently that very few small fragments are generated. If the latter, you need to combine use of this enzyme with a 4-bp cutter in order to generate fragments that are amplifiable by PCR. Enzyme combinations that, in our hand, have worked great for a variety of species is the enzyme combination PstI and MspI.