File Size & Posting Limits
Every platform sets its own limits for photo and video uploads. Here's what each one accepts, so you know your posts will go through.
The rule that matters most: when you post the same file to several platforms at once, the smallest limit among them applies. StudioFlows checks your file as you build the post and automatically greys out any platform it's too big or too long for — so you'll never get a surprise failure after scheduling.
Video limits
Videos must be MP4 or MOV format.
| Platform | Max file size | Max length |
|---|---|---|
| Instagram (Reels) | 300 MB | 15 minutes (3 sec min) |
| TikTok | 1 GB | 10 minutes |
| YouTube | 5 GB | Up to 4 hours (Shorts ≤ 60 sec) |
| No fixed cap (bitrate-limited) | 20 minutes | |
| X (Twitter) | 512 MB | 2 min 20 sec (free accounts) |
| 2 GB | 30 minutes | |
| Threads | 1 GB | 5 minutes |
| 2 GB | 15 minutes (4 sec min) | |
| 1 GB | — | |
| Snapchat | 100 MB | 60 seconds (5 sec min) |
| Mastodon | 99 MB | 5 minutes |
| Bluesky | — | 5 minutes |
Photo limits
Photos are JPG or PNG. "Photos per post" is the max for a single carousel/multi-image post.
| Platform | Max file size | Photos per post |
|---|---|---|
| 8 MB | 10 | |
| TikTok | 20 MB (JPG only) | — |
| 4 MB | 4 | |
| X (Twitter) | 5 MB | 4 |
| 5 MB | 10 | |
| Threads | 8 MB | 10 |
| 5 MB | 1 | |
| 20 MB | — | |
| Snapchat | — | 1 |
| Mastodon | 16 MB | — |
| Google Business | 5 MB | 1 |
| Bluesky | 1 MB | 4 |
Custom YouTube thumbnail: up to 2 MB. YouTube Shorts don't support custom thumbnails.
Do these limits change by how I post?
No — the same platform limits above apply however you create the post:
- Manual posts: the composer checks your file live and disables any platform it exceeds before you schedule.
- Hot Folder (desktop upload): drop a file in your watched folder and it posts with the same limits. Large files upload fine.
- Auto Posting (scheduler): posts your photos on your set schedule, using the photo limits above.
Web Watch
This is separate from posting. Web Watch tracked images can be up to 30 MB each (JPG, PNG, or WebP) — StudioFlows compresses them automatically during upload, so you can drop in full-size exports.
Still have a file that won't post?
Send us the details and we'll help you get it live.
Contact Support