Fix research images

pages/research/research-overview.mdx

@@ -18,7 +18,7 @@ This document provides an overview of Optimism’s approach to research and expe
 
 Below are the key principles guiding our approach to experimental design. Our goal behind each of these principles is to take a thoughtful, data-driven approach as we iteratively design a resilient governance system. 
 
-![Principles for Designing Experiments.png](https://prod-files-secure.s3.us-west-2.amazonaws.com/4b8b38c3-9876-41aa-bbe3-0f23be2b6ab4/6c14bffb-0a70-4dd8-8000-f88f96a1d262/Principles_for_Designing_Experiments.png)
+![Principles for Designing Experiments](/img/research/experiment-principles.png)
 
 *A note on the principle that **randomization = causal learning**:* Across disciplines and settings, causal learning requires randomization, because random assignment to treatment group ensures that the observed and unobserved characteristics are balanced evenly between treatment and control groups. Importantly, this removes selection bias (or other types of omitted variable bias) that otherwise influences results. Because of this, when possible, we aim to randomly select treatment and control group participants in our experiments. 
 
@@ -35,7 +35,7 @@ If teasing out causation via a quasi-experiment is also not possible, then we si
 
 As we’ve discussed above, experiments are well-suited for a specific type of question (i.e., about cause and effect), though it’s sometime impractical to experiment with human behavior. And finally, experiments also take resources and time to execute well. With this in mind, here’s how we think about when to experiment: 
 
-![Should this be an experiment_.png](https://prod-files-secure.s3.us-west-2.amazonaws.com/4b8b38c3-9876-41aa-bbe3-0f23be2b6ab4/398b17a4-6543-402d-87e9-990df8dd0623/Should_this_be_an_experiment_.png)
+![Should this be an experiment](/img/research/experiment.png)
 
 1. **Is this mission-critical?**
     1. ***If yes, the research question is about existential parameters, then we want to experiment (if the next two answers are also “yes”)***