Replacing warning image in explore doc (#15045)

## DESCRIBE YOUR PR
Replacing warning image in explore doc. 

image:
https://sentry-docs-git-replace-sampling-warning-img.sentry.dev/product/explore/trace-explorer/#sampling-warnings

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## PRE-MERGE CHECKLIST

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- [ ] Checked Vercel preview for correctness, including links
- [ ] PR was reviewed and approved by any necessary SMEs (subject matter
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Co-authored-by: Shannon Anahata <[email protected]>

Author: sfanahata

docs/product/explore/trace-explorer/img/Trace_explorer_low_samples.png

@@ -185,7 +185,7 @@ Similarly, Sentry incorporates the weight into **sum**:
 
 Trace Explorer will display **Sum: 1.4ms**.
 
-### Averages and percentiles
+### Averages and Percentiles
 
 Averages and percentiles are **weighted**. You don't just average the 2 spans -- Sentry accounts for the fact that they represent a larger dataset. For example, the weighted average works like this:
 
@@ -199,7 +199,9 @@ Sentry treats this as a representation of the average across all 12 estimated sp
 
 If your sampling rate is **too low** for an accurate extrapolation (for example, keeping less than 5% of an already low number of spans), Sentry may show a **low sampling rate warning**. This lets you know that extrapolation might be less reliable, especially for more restrictive queries.
 
-![Trace Explorer Screenshot](./img/Trace_explorer_low_samples.png)
+<div style={{width: '450px'}}>
+![Trace Explorer Warning](./img/Trace_explorer_low_samples.png)
+</div>
 
 Even if you sample your spans, **Trace Explorer's extrapolation gives you reasonably accurate answers** for counts, averages, and percentiles -- without you needing to do anything extra.