Q. How do I find information on a company's corporate or brand image?

Companies don't often distinctly articulate their image. However, through using articles on the company and company information, you should be able to extract relevant information.

Encyclopedia of Global Brands

Provides a good overview of branding for major companies. 

Annual reports

Review their annual reports for imagery and phrases.

See Mergent Online

Articles

Review articles from the business literature. Search for the company name in combination with image or brand image etc. 

See Business Source Complete and ABI Inform (for Canadian companies see CBCA Complete). 

Press releases

Review their press releases for important phrases and branding. 
See the company's website as well as Factiva.