Fix Illustration Grey Artifact on landing, sub pages

[liz-shinn]

Problem: Illustrations on the Threshold website have an extra gray rectangle in them, an artifact from the PNG export.

• [x] Fix the images in Figma so that they export correctly.
• [x] Export them.
• [x] Dev help needed (cc/ @r-czajkowski or @michalsmiarowski when you have a spare cycle?) to replace the images.

Screenshots in the comments of the images that need to be replaced.

Example of the square i'm referring to:

[liz-shinn]

Images that are wrong:

Threshold Staking image

• Replace it on the home page
• Replace it on the sub page in Earn

---

Threshold tBTC image

• Replace it on the home page
• Replace it on the sub page in Earn

---

Threshold Liquidity Provider

• Replace it on the home page
• Replace it on the sub page in Earn

---

Threshold Token Holder image

• Replace it on the home page
• Replace it on the sub page in Earn

[liz-shinn]

✅ Corrected images ✅