I am no veteran blogger by any means but I am all about efficiency and these are my essentials to make life that much easier.
For Making Collages- Blogstomp
First and foremost get Blogstomp. It was seriously the BEST investment I ever spent for the blog. I was initially turned off by the $50 price tag but I found a coupon code (naturally) and it is the biggest time saver ever. Basically it takes your very large photos and “stomps” them to a much smaller size but it maintains the high quality of them. Therefore your page will load much faster. You can also set your width so all the pictures are the same. Also if you want to watermark all your pics when you “stomp it” it adds the watermark wherever you want it to. I use to use Pic Monkey because it was free but this seriously is so much faster and easier. Plus when you want to make collages it is insanely easy. For example.
Here are my pictures from the recent Fall Outfits I was digging post. They are all very large files because I took it with my DSLR camera. So you open them all and the grab the ones you want to put into a collage. Pick the collages on the right you like the best and you can even mix it up (rearrange how the pictures go into the collage).