Tumblr is the outlier in almost every cross-posting set, and it’s the platform people most often under-use because they send it a version written for somewhere much tighter.
What Tumblr accepts
Through BulkPublish:
| Post length | 32,768 characters |
| Images | Up to 30, 20 MB each, JPG, PNG, GIF or WebP |
| Video | Up to 500 MB and 600 seconds, MP4 or MOV |
Those numbers are worth sitting with. Thirty-two thousand characters is over a hundred times X’s limit. Thirty images in one post. Ten minutes of video.
Tumblr is closer to a blogging platform than a microblogging one, and its posts behave accordingly: long-form works, image sets work, and posts have a long tail through reblogs rather than a short spike.
The mistake: sending it the short version
If Tumblr is one destination in a cross-posting set, the default is that it receives whatever was written for the tightest platform in that set. A 280-character post on a platform that accepts 32,768 looks like a fragment.
Worse, it misses how Tumblr content actually travels. Reblogs mean a good post keeps circulating long after it was published, which rewards posts with enough substance to be worth resurfacing. A one-line post has nothing to reblog.
If Tumblr matters to you, write it its own version. That doesn’t mean writing an essay for every post. It means when there’s more to say, Tumblr is where you say it.
Scheduling one
- Connect your Tumblr blog
- Write the post, using the room if you have something to fill it with
- Attach images or video
- Pick a date and time and queue it
Media and length are validated before the post is queued, though with these limits you’re unlikely to hit them.
Image sets
Thirty images in one post is unusual, and it’s genuinely useful for the kind of content Tumblr is good at: photo sets, process documentation, collections, sequences.
Most tools and platforms cap you far below this, so if you have a set of images that belong together, Tumblr may be the only place in your cross-posting group that can hold them all in one post.
Tumblr alongside everything else
The workable pattern is one draft, adapted:
- Short networks get a trimmed version
- Instagram and Pinterest get the visuals
- Tumblr gets the fuller text and the complete image set
That’s the same content and one workflow, not four separate posts.
BulkPublish publishes to Tumblr and 14 other networks: Facebook, Instagram, TikTok, YouTube, X, Threads, Bluesky, Pinterest, Google Business Profile, LinkedIn, Mastodon, Discord, Telegram and Snapchat.
- Channels: Free: 3 (1 per platform). Pro: 30 (2 per platform). Business: 75 (5 per platform).
- Posts: Free: 3/day. Pro: 30/day. Business: unlimited.
- Storage: Free: 100 MB. Pro: 2 GB. Business: 10 GB.
With 20 MB images and 500 MB video allowed, the storage tier on your plan is worth checking if you post image sets regularly.
The short version
Tumblr takes 32,768 characters, 30 images and 10 minutes of video, which is more room than anywhere else you post. The mistake is sending it the version you wrote for a 280-character platform. Write Tumblr its own version when you have something worth the space, and use the image sets, because almost nowhere else lets you.