docs: remove GitHub-specific Markdown in README.md

README.md

@@ -29,8 +29,7 @@ You can `pip install` Ibis with a backend and example data:
 pip install 'ibis-framework[duckdb,examples]'
 ```
 
-> [!TIP]
-> See the [installation guide](https://ibis-project.org/install) for more installation options.
+See the [installation guide](https://ibis-project.org/install) for more installation options.
 
 Then use Ibis:
 
@@ -71,8 +70,7 @@ Then use Ibis:
 └───────────┴───────────┴───────┘
 ```
 
-> [!TIP]
-> See the [getting started tutorial](https://ibis-project.org/tutorials/getting_started) for a full introduction to Ibis.
+See the [getting started tutorial](https://ibis-project.org/tutorials/getting_started) for a full introduction to Ibis.
 
 ## Python + SQL: better together
 
@@ -165,7 +163,7 @@ Ibis broadly supports two types of backend:
 1. SQL-generating backends
 2. DataFrame-generating backends
 
-![Ibis backend types](docs/images/backends.png)
+![Ibis backend types](https://raw.githubusercontent.com/ibis-project/ibis/main/docs/images/backends.png)
 
 ## Portability
 
@@ -200,10 +198,7 @@ You can also read from common file formats like CSV or Apache Parquet:
 >>> t = con.read_parquet("penguins.parquet")
 ```
 
-This allows you to iterate locally and deploy remotely by changing a single line of code.
-
-> [!TIP]
-> Check out [the blog on backend agnostic arrays](https://ibis-project.org/posts/backend-agnostic-arrays/) for one example using the same code across DuckDB and BigQuery.
+This allows you to iterate locally and deploy remotely by changing a single line of code. Check out [the blog on backend agnostic arrays](https://ibis-project.org/posts/backend-agnostic-arrays/) for one example using the same code across DuckDB and BigQuery.
 
 ## Community and contributing