Praise be to Allah
The fasting person is not allowed to eat or drink during the day, and he should do that (fasting) for the sake of Allah and seeking reward with Him.
Allah, may He be exalted, says (interpretation of the meaning):
“and eat and drink until the white thread (light) of dawn appears to you distinct from the black thread (darkness of night), then complete your Saum (fast) till the nightfall”
Al-Bukhaari (7492) and Muslim (1151) narrated from Abu Hurayrah that the Prophet (blessings and peace of Allah be upon him) said: “Allah, may He be glorified and exalted, says: ‘Fasting is for Me and I shall reward for it; he gives up his desire and his food and drink for My sake.’”
Showing pictures of food and drink to one who is fasting in order to annoy him, weaken his resolve or tempt him to break the fast is an unlawful action that is contrary to the aims of the Lawgiver, and it is of the work of Iblees who lies in wait for the believer on every path, to bar him from the truth, as Allah says concerning him (interpretation of the meaning):
“and Shaitan (Satan) has made their deeds fair-seeming to them, and has barred them from (Allah’s) Way, so they have no guidance”
“(Iblees) said: ‘Because You have sent me astray, surely I will sit in wait against them (human beings) on Your Straight Path.
‘Then I will come to them from before them and behind them, from their right and from their left, and You will not find most of them as thankful ones (i.e. they will not be dutiful to You)’”
[al-A‘raaf 7:16, 17].
If doing this action is unlawful, then doing it by way of joking is makrooh (disliked), and is not appropriate. Rather what is appropriate is to show respect to what Allah has enjoined, and encourage and help people to do it. Perhaps these images may tempt those who are weak in faith to break the fast, in which case the one who made this joke will incur a burden of sin as a result.
If the aim really is to annoy the fasting person, by making him feel that he is missing out by being deprived of this delicious food, or to weaken his resolve or make the idea of breaking the fast attractive to him, then this is a haraam and unlawful act because it is contrary to what the Lawgiver wants, as mentioned above, and because it is calling people to sin and disobedience.
And Allah knows best.