I am trying to update my resume, and I am having kind of a hard time. I am working a summer job and last year I was an assistant in this role now I am the role. The only different I see is that I see is mostly record keeping, evaluating the staff, and that the staff I oversee and trained is smaller than last year. When putting this new job, should I just put under that title only the new things or should I repeat the previous things from the assistant title, having those on my resume twice.

The reason why I am updating my resume is that I am looking to apply to a job. The job required skills and experience section says they are looking for experience with social media platforms, seems mostly interested in Twitter and Instagram, and experience with Adobe Creative Suite, specifically Photoshop and InDesign, but they said this is a plus. I do have experience using social media, Instagram and Twitter are basically the only ones I use anymore, and I have in the past used Photoshop and other photoshop like tools. I haven't had to use these things in previous job experiences. How should I bring this up? Putting it in the cover letter seems like I am throwing it in. Should I put it in a skills section just to say I have experience?