How can I convert gif images to text files?
Another free one people forget sometimes is the DocMorph: http://docmorph.nlm.nih.gov/docmorph/docmorph.htm. You'll want to register for free, then choose to "Extract Text" and then upload your image.
I take it that the gif images contain text. What you are looking for is 'optical character recognition' (OCR). Check out these articles:
Top 5 Free OCR Software Tools To Convert Images Into Text
How To Extract Text From Images (OCR) – Windows Only
Convert Images To Text Online With Free OCR