If you are on a mac and need to batch rename a lot of files Finder has this function built into the system now: http://osxdaily.com/2015/05/28/batch-rename-files-mac-os-x-finder/
Your website resizes images on-the-fly, so they will fit any size screen, which is super exciting, but means you must take a few special steps to prepare the images you upload.
1. Upload a large image (don't worry we make smaller versions for mobile devices and ipads): Your ideal image size is 1860 x 1140 pixels for a horizontal (930 x 1140 for a vertical). No need to crop your image, just make one of those dimensions the biggest (i.e. 1860 x 1072 or 1700 x 1140).
NOTE: For the 4 and 5k screens people are using now you might consider 2400 x 1600 (horizontal) for sizing your images.
2. Use "Save For Web" in Photoshop or the equivalent in lightroom "File –> Export": You want the images in the 250 - 550 kb range (the less colors the easier it will be to get it lower), so use a lower quality setting to get it down there. When saving for web make sure you include a color profile and XMP so your caption and copyright remains.
This video will help you with image resizing:
Watch this Video to see how to batch resize all your images at once:
3. Name your images properly: Avoid using anything but letters, numbers, underscores and dashes (and only one period before the jpg) when naming your images. Each image must have a unique name.