Migrate images from strategy.data.gov/assets to resources.data.gov

## Summary

Three images hosted on `strategy.data.gov` are embedded in a resources.data.gov content file. These must be migrated before the strategy.data.gov redirect goes live or they will break.

## Background

`pages/_resources/fdspp-pr-emergency-response.md` references three images at `strategy.data.gov/assets/img/posts/`:

- `2019-07-28-image002.png`
- `2019-07-28-image003.png`
- `2019-07-28-image004.png`

## Tasks

- [ ] Copy the three image files to the appropriate assets directory in `GSA/resources.data.gov`
- [ ] Update the three image paths in `pages/_resources/fdspp-pr-emergency-response.md` to point to the new location
- [ ] Confirm images render correctly on a preview build

## Acceptance criteria

- [ ] All three images load from resources.data.gov URLs
- [ ] No remaining image references to `strategy.data.gov` exist in the resources.data.gov repo

## Blocks

Ticket 3 (CSP header update), Ticket 6 (redirect)