It comes from the Proto-Slavic word *milъ (sweet, dear), from the Proto-Indo-European word *meh₁y- (mild, soft).
The Czech word milý (nice, kind, good, dear, pleasant, sweet; boyfriend) comes from the same root, as do similar words in other Slavic languages, such as the Belarusian мілы (sweet, nice), the Bulgarian мил (dear), and the Polish miły (nice, pleasant).
The Latin mītis (gentle, mild, ripe) comes from the same Proto-Indo-European root, as does the Italian word mite (mild, moderate, balmy), the Portuguese word mitigar (to mitigate), the Spanish word mitigar (to mitigate, alleviate, allay, assuage, quench, soothe), and the English word mitigate.
In most Slavic languages the word for bread is chleb or something similar: Czech & Polish: chleb, Slovak: chlieb, Russian & Belarusian: хлеб, Ukrainian: хліб, Bulgarian: хляб, Macedonian: леб.
These words all comes from the Proto-Slavic *xlěbъ (bread), from the Proto-Germanic *hlaibaz (bread). [source]. *hlaibaz is also the root of the English word loaf, the German Laib (loaf), and words for loaf in other Germanic languages [source].
However, in Slovenian the word for bread is kruh, which means circle or ring in Czech, although the Czech word probably comes from a different root [source]. It comes from the Proto-Slavic *kruxъ (chunk, bread), which comes from *krews (crush, break) [source].
The bread in the photo is a type of Slovenian potato bread known as krompirjev kruh. You can find recipes here (in Slovenian) and here (in English).