Single image
JPG, PNG, or GIF. Maximum 5 MB. Animated GIFs: no more than 250 frames. Destination URL up to 2,000 characters.
Portrait serves on mobile, so include it if your audience skews mobile.
Video
MP4. 75 KB to 500 MB. Duration 3 seconds to 30 minutes, with 15–30 seconds recommended for the broadest placement eligibility. SRT caption files are supported.
Carousel
Each card can point at a different destination URL, which makes carousel useful for a multi-product or multi-offer set.
Copy limits
LinkedIn’s “recommended” counts are truncation guidelines — the point at which text gets cut off in the feed. The input maximums are considerably longer. Write to the recommended figure; treat the maximum as headroom, not a target.