One cannot build applications without the connection with such sharing sites, but the actual logistics of getting this done can be complex. One of these areas revolve around all the icons and others used in the application. Now, for the most part, most applications with a large number of user interfaces use their own customs icons and graphics, these having been made to seem to fit with the application (in terms of the image that the application seeks to present, the customer profile that it tries to fit, as well as the functionality that is being done in the application - an application that is dealing with money or finances would have more icons that have some sort of representation of money or cash, while applications dealing with images would show more of cameras or images, etc). Another use of these custom icons is that they present the same set even if the application is installed on Windows or on the Mac (while the application system icons on these different OS's are very different).
However, when interfacing with these 3rd party icons, there needs to be careful coordination with the team that is developing the custom icons. As part of the public API's available for most of these networks, they also have a list of icons that client applications need to use, and in some cases, the icon may drastically vary from the icons used in the application. It is typically not possible to get variations in the icons provided by these 3rd party services, although some of them will provide multiple icon sets at different sizes to ensure that one of them is suitable, but that may not be the case. Further, the team designing the custom icons may not be aware that there is a legal requirement to use only the service icons, and they should be kept informed so that they do not try to develop customs icons for these networks when only the service provided icons can be used.
In addition, if the icons provided by the services are striking on their own and different from those in the application, it would help if the designer team already knows this in advance, and hence can ensure that the icon set that they are designing for the application is made in a way that the service provided icons fit with the service. But, from time to time, these 3rd party services also go in for a rebranding, and require all clients using their services to also change the icons that they are using, which means that somebody needs to keep track of communication from the external services regarding their branding and icons.