You can use VideoPower RED. It has a downloader and converter to mp3 function.
Here is a related article as a guide.
videopower.me/tips/ct-convert/how-to-convert-a-YouTube-video-to-mp3/
Just use the copy and paste URL method for your Tumblr videos to download
It's free. You can also download Tumblr videos using this videopower.me/tips/ct-download/download-tumblr-video-2/
You can buy them from online sellers, or you can search through Livejournal and Tumblr tags for audio and download links.
Simply login to Tumblr from the Dashboard go to your blog. Click on Audio and add audio as per your requirement by means of direct URL. You can also upload audio. Fill the necessary details and create post.
Adding music to your tumblr is tacky and is advised that you don't.
theres a google chrome plug in for it.
download audio driver
Yes. I am using VideoPower RED for my Tumblr video downloads. It's easy and it pretty much works. This how-to article could help you videopower.me/tips/category-videopower-red/easily-download-tumblr-video/
Many online sites have beautiful free tumblr themes. Some of these online sites that carry free tumblr themes are "Themesthatyoulike", "The-theme-gods", and "Mashable".
You can get the audio books on iTunes or stepheniemeyerbooks.com
download the audio files and then insert them
A good tumblr music player is the SCM Music Player. You can Google it to take you to the site. Mixpod is also a good audio player, though it has a few flaws.
Your GIF is most likely not moving because it is too large for Tumblr. Tumblr GIFs have to be under 500mb or else they won't move. To remedy this problem you can try resizing your GIF to a smaller size!