I would argue it is either 1) neither necessary nor sufficient, or 2) that it is sufficient but not necessary. Which line depends on whether we are talking about something literally BEING a meme, or something merely having the potential to be a meme.
In the former case - whether something is a meme or not - having text is neither necessary nor sufficient. Adding text to an image does not a meme make, and equally some memes do not have text (or aren’t images at all).
In the latter - whether something could be a meme - adding text is sufficient to provide that potential. It may not be necessary (6-7 for example) but it could be enough.
I would argue it is either 1) neither necessary nor sufficient, or 2) that it is sufficient but not necessary. Which line depends on whether we are talking about something literally BEING a meme, or something merely having the potential to be a meme.
In the former case - whether something is a meme or not - having text is neither necessary nor sufficient. Adding text to an image does not a meme make, and equally some memes do not have text (or aren’t images at all).
In the latter - whether something could be a meme - adding text is sufficient to provide that potential. It may not be necessary (6-7 for example) but it could be enough.