Update README.md

Author: michalchudziak

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-  <img alt="React Native Brownfield" src="https://user-images.githubusercontent.com/7837457/63594721-7f7b8800-c5b7-11e9-87ef-a0898cd22fcc.png" width="800">
+  <img alt="React Native Brownfield" src="https://user-images.githubusercontent.com/7837457/63594721-7f7b8800-c5b7-11e9-87ef-a0898cd22fcc.png" width="600">
 </p>
 
 <p align="center">
@@ -113,4 +113,4 @@ This project follows the [all-contributors](https://github.com/kentcdodds/all-co
 [tweet-badge]: https://img.shields.io/badge/tweet-%23reacnativebrownfield-blue.svg?style=flat-square&colorB=1DA1F2&logo=data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABgAAAAUCAYAAACXtf2DAAAAAXNSR0IArs4c6QAAAaRJREFUOBGtlM8rBGEYx3cWtRHJRaKcuMtBSitxkCQ3LtzkP9iUUu5ODspRHLhRLtq0FxeicEBC2cOivcge%2FMgan3fNM8bbzL4zm6c%2BPT%2Fe7%2FO8887svrFYBWbbtgWzsAt3sAcpqJFxxF1QV8oJFqFPFst5dLWQAT87oTgPB7DtziFRT1EA4yZolsFkhwjGYFRO8Op0KD8HVe7unoB6PRTBZG8IctAmG1xrHcfkQ2B55sfI%2ByGMXSBqV71xZ8CWdxBxN6ThFuECDEAL%2Bc9HIzDYumVZ966GZnX0SzCZvEqTbkaGywkyFE6hKAsBPhFQ18uPUqh2ggJ%2BUor%2F4M%2F%2FzOC8g6YzR1i%2F8g4vvSI%2ByD7FFNjexQrjHd8%2BnjABI3AU4Wl16TuF1qANGll81jsi5qu%2Bw6XIsCn4ijhU5FmCJpkV6BGNw410hfSf6JKBQ%2FUFxHGYBnWnmOwDwYQ%2BwzdHqO75HtiAMJfaC7ph32FSRJCENUhDHsLaJkL%2FX4wMF4%2BwA5bgAcrZE4sr0Cu9Jq9fxyrvBHWbNkMD5CEHWTjjT2m6r5D92jfmbbKJEWuMMAAAAABJRU5ErkJggg%3D%3D
 [tweet]: https://twitter.com/intent/tweet?text=Check%20out%20react-native-brownfield!%20https://github.com/callstack/react-native-brownfield%20%F0%9F%91%8D
 [callstack-badge]: https://callstack.com/images/callstack-badge.svg
-[callstack]: https://callstack.com/open-source/?utm_source=github.com&utm_medium=referral&utm_campaign=rnbrownfield&utm_term=readme
+[callstack]: https://callstack.com/open-source/?utm_source=github.com&utm_medium=referral&utm_campaign=rnbrownfield&utm_term=readme