Dedicated text to image converters are your best shot for .txt to .jpeg conversion. For example the online TEXT to IMAGE converter can be used for exactly this purpose, generating a image from preferably ASCII art.
Convert Simple text file to JPEG bitmap image format.
We have found one software suitable in our database for this conversion.
On-line services software - convert txt to jpeg on web
An online text to image conversion service
Convert from txt file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.