The reason the LinkedIn app is so big is the number of frameworks they use. 87 frameworks accounting for 248MB of the 277. The swift runtime takes up about 20MB, and something called VoyagerFeed takes up over 190. All the images actually only make up about 12MB. There's also about 0.5MB for each localisation.
iamatworknow|8 years ago
"LinkedIn’s new flagship app, nicknamed “Voyager,” is a complete architectural and design overhaul available for iOS and Android, as well as an online mobile experience, in the coming weeks." https://thenextweb.com/apps/2015/10/14/linkedin-voyager/
Sounds like "VoyagerFeed" may be part of their own codebase.