• Leveraging high image rankings: You may have top rankings for your images in both the image results and universal/blended results but what are visitors doing when they arrive at your site? Search Engines such as Google show the exact page where an image resides (after clicking throuh on an image) therefore this is a great opportunity to funnel visitors deeper to your site. The different images queries which refer visitors to your site can help dictate the type of content you should surround your images with.
• Should you freshen up your images? You definitely should. Similar to textual content, keep visitors coming back with images that continue to match the visitor's query (and intent). The most important point is to maintain the names of the images as well as the textual content within the alt attribute.
• The ROI on Video: Video is an excellent way to promote your brand and services to visitors but how do you know when a given video has maxed out its potential. I recommend checking out trends for views, comments and clickthroughs (and again what visitors are doing after the click through). These trends should help show whether or not the video is still engaging visitors. If you are seeing the trends flat-line you know it's time to add some new content.
• Visitors know what they like to watch: If you're thinking about enhancing your video strategy with some fresh content then I suggest you look to your visitors for help. Look at the comments they leave (if you've uploaded YouTube or MetaCafe) and secondly look at your internal search terms. Both of these areas are ways visitors have engaged with your content by providing feed back so why not show visitors what they want?

Bonus Tip*

This next strategy is not directly related to video or images but the concept is something you maybe able to apply elsewhere. I have two travel sites: BC Travel Guide (.ca) and British Columbia Tours (.com) and I am looking to rank highly for "Kelowna" or "Kelowna British Columbia." So I created a Kelowna themed page on each site, both with keyword rich content, interlinking and images. The results are too early to tell but this allows me to test the level of authority per domain, the return per domain and the potential for having 2 sites rank highly for a few phrases.