In Russia, in the period from the 1530s to 1540s, Metropolitan Makariy/Macarius of Moscow supervised the compilation of a series of twelve books known as the Великие Четьи-Минеи (Velikiye Chet’yi-Minei), The Great Menaion Reader, or Great Monthly Reader. It contains lives of saints for each day of every month (thus the twelve volumes), as well as other ecclesiastical writings. It is said that Makariy even consulted the exiled Maxim the Greek and included some of his writings in it, but still refused to pardon him for his supposed “heresy.” But for our purposes here, its significance is that all of these newly-collected saints’ lives contributed to the rise in Russia in the latter half of the 1500s of the type of icon called a минея/mineya — an icon depicting the saints and major festivals for any given month of the year. So there is the term икона-минея/ikona mineya — a “month icon.” It is also called месячные святцы/mesyachnuie svatsui — “monthly saints.”
A complete set comprises twelve icons. In English, you will often see such an icon listed under the term menaion, from the Greek μηναῖον/menaion, meaning loosely “monthly.” Sometimes more than one month was included on the same panel. When an icon depicts the saints for the whole year on a single panel, it is called a минея годовая/mineya godovaya — meaning “year mineya” — that is, a year icon.
There are so many saints commemorated in each month that it would be difficult to fit them all onto a panel, so usually “month” icons show only major saints — and not always exactly the same saints from set to set. Also, because painting such a set of twelve icons with the saints for each day as well as church festivals was a great amount of work, not all such icons were carefully painted, and many were done not only in a hurried fashion but also often in a limited color palette instead of using the colors for each saint’s garments as listed in the painters’ manuals.
“Month” icons were primarily used in churches, where the icon for the present month could be put out on an icon stand (analoy) for all to see.
Most “month” icons depicted only saints and other festal commemorations, leaving out the many so-called “wonderworking” icons of Mary that also have their days of commemoration. Some, however, included them. One may find “year” icons with an entire border of “wonderworking” icons of Mary.
Here is an example of a rather well-painted “month” icon for December:
Now if we compare it to another December icon, we see something rather odd:

It is in the middle of the third row down:
There it is: an icon of the Resurrection, painted in a simple manner. It was not in the first example, so why is it in the second?
Now as you know, the Resurrection of Jesus is not celebrated in December. It is a moveable feast that comes either in April or early in May, depending on the year.
I never paid much attention to this oddity, which is found not only in this icon but in many “month” icons, until a reader in Italy pointed it out to me. Some “month” icons depict the Resurrection not only in April or May, but in other months as widely separated as January and August. It does not mean, however, that the commemoration of the Resurrection is actually in that particularly month, but rather it was just something icon painters at times would add to a month icon, though really it had no place in the calendar for that month.
Sometimes the Resurrection is depicted in the middle of the top row in a “month” icon, as in this one for February, which interestingly shows it in the “Western” form of Jesus above his empty tomb:
At other times, a Resurrection image is placed right in the center of the icon, as in this example for the month of May:

Here is an example in which the Resurrection is placed at the top, above the rows of saints for the month of December:

Here it is:
So, don’t be surprised if you find a depiction of the Resurrection in a “month” icon where it does not calendrically belong. It is just another of those peculiar things about Russian icons.