Sqlite database designing

My app loads and parses data to an Article objects. I need to store articles in a database to access them offline. Each article has fields:

• Title (Text)
• Text (Text)
• Date (Text in specific format)
• Tags (Text)
• Link (Text)
• Preview image (Blob)
• Full image (Blob)
• Related articles

Each related article has fields:

• Title (Text)
• Link (Text)

• Preview image (Blob)

  1. Should I create a new database for related articles or store them in the existing database? What is better for performance and what is better for designing?
  2. Should I store preview and full image? Or maybe it's better to scale existing full image to preview format in app? (app performance vs extra data storage)

I know that it usually depends on the circumstances, but I want to know what is usually the best practice.