Add logo and welcome, update lodging text

Author: effigies

README.md

@@ -1,5 +1,9 @@
 # Nipreps sprint, Cambridge, MA, April 30 - May 2, 2025
 
+![image](https://github.com/nipreps/nipreps.github.io/blob/mkdocs/docs/assets/nipreps-transparent.png)
+
+Thank you for participating in the 2025 Nipreps sprint!
+
 The purpose of this meeting is to advance Nipreps development. <br>
 Participants will work in small groups on existing nipreps projects and find points of overlap and new collaborations.
 
@@ -31,9 +35,9 @@ if that is a more convenient way to organize work.
 
 ## Lodging and Logistics
 
-All in-person participants should have received instructions to set up an account
+All in-person participants should receive instructions to set up an account
 that will allow us to book their flights and hotels, if needed.
-Please contact Oscar Esteban or Chris Markiewicz immediately if you have not.
+Please contact Oscar Esteban or Chris Markiewicz if you have any questions.
 
 ## Questions?