unable to understand confusion. you can actually choose and pick some uncovered things from these press sections that others have not given attention to. anyway, will give you way out to get enough high quality pictures for a steady stream of content, considering that no specific models have come up so far.
use press resources
use images with credit
screencap from videos
for prototypes, and in development projects, again videos in their youtube channel is the best bet considering you need images for web only
the above should cover most scenarios for new laptops, mobiles..
for ones that you dont have skip. now these top blogs also use media from these press kits, some live tweet releases and go to tradeshows. indie bloggers also get invites to cover events, so get going with networking, being in touch with the pr of these companies is a great way to start if the images are not available in the press/news or the listing of current models section. you do have a window of opportunity to quickly cover the release, and post a review before anyone else.
PS is there good photo of something you haven't got so far?