Nope! Unlike the web service, there’s no limit to how big your boards can be if you press that Share button from the Boards section of the app.
The sky's the limit. However, you'll need to make sure you have enough storage space as a copy of the files will be created in the app itself, it does not reference the files already on your device.
Keep in mind that while you can share your files without a size limit, this does not mean that Collect will automatically store all your files in the cloud. With the free version of Collect, there is a 5 GB limit.
If you are interested in getting 200 GB of Cloud Storage, read more about Collect Pro subscription plans by clicking here.
Happy collecting!