Is Silent Image animated if an action is not used to move it?

Question

You can use your action to cause the image to move to any spot within range. As the image changes location you can alter its appearance so that its movement appear naturel for the image.

So, we know that when the caster use an action to move the image, the movement appears natural. But what happen if the caster uses his action to do something else, like, cast a firebolt? Will the image become perfectly still?

Let's say a caster uses his action to cast the image of a campfire with silent image.

1. Will the flames flicker naturally? Or does he have to use his action so the flames keep moving? What happen if he doesnt use his action? Do the flames froze and become perfectly still?

2. When casting silent image to create the image of a campfire, can the caster make it looks like the fire is lighting up (starting from a spark then grow)

Answer 1

Probably Not, that's what higher level illusions are for

Your quote for Silent Image covers what you can do with it (emphasis mine):

You can use your action to cause the image to move to any spot within range. As the image changes location, you can alter its appearance so that its movements appear natural for the image.

Let's go over your questions:

1. Will the flames flicker naturally? Or does he have to use his action so the flames keep moving? What happen if he doesn't use his action? Do the flames froze and become perfectly still?

   In this case the object would remain the object and most likely be still. Whether or not a campfire would be an object will be up to the DM. In order to have the Silent Image move RAW, it must move to a new spot within range. As the image moves to that spot, the appearance is altered to appear natural. You'd need to move the campfire around in order for the flames to flicker, etc.

2. When casting silent image to create the image of a campfire, can the caster make it looks like the fire is lighting up (starting from a spark then grow)

   No. Again, the way for Silent Image to 'move' is to have shift locations and it will create a natural appearance of movement.

Campfire maybe, Light No.

As shown in this question Silent Image does actually produce light or simulate it. You may have an image of an object, but it's a static image that does not have "any other sensory effects."

Major Image has the additional language:

It seems completely real, including sounds, smells, and temperature appropriate to the thing depicted.

You could emulate terrain on fire with Hallucinatory Terrain and Mirage Arcane, which states:

You make natural terrain in a 150-foot cube in range look, sound, and smell like some other sort of natural terrain.

Silent Image can do a lot of things, but it is not a replacement for higher level illusion spells like Major Image, Hallucinatory Terrain, Programmed Illusion, Mirage Arcane, etc.

You may argue that light is light, but in this case, illusions do not work like. See the following questions for additional support:

• Can you create an illusion of empty space?

• Can you use Minor Illusion to create an illusion of a working mirror, i.e. with reflection?

Answer 2

Like most the effects it would depend on your DM, but I don't see anything wrong with passive movement of a silent image, so long as it fits the other parameters of the spell. There are alot of definitions of 'image', I see the best one being 'visual representation of a mental picture.' So if it has movement when you bring up the mental picture, then it can have passive movement (IMO). That said, the most important thing is to describe your intent of using the illusion in the first place and then it can be determined if the illusion you are casting fits the intended purpose of the silent image.

For instance, if you want to use the fire as a choke point for goblins because they fear fire...well if goblins act on instinct, seeing a fire appear would likely work, whether or not the flames a flickering. A more intelligent creature, not acting out of fear might notice no smoke, heat or smell of a fire and thus be prompted to make an investigation check, or just ignore the fire. Whether or not the image is moving is storytelling; so long as the mechanics of what your are doing are clear and the purpose of casting the illusion fits with the spell slot you are forfeiting to use it, I think it's fair game/not ignoring RAW (that is I don't believe it says that there can be no passive movement to the image, and the movement for action refers to actually moving it within the spells range. Crawford stated silent image could be used to create images with movement, such as a fountain, though it is still unclear to me weather that would require action in combat, but it is unlikely to have meant you have to move it to a different location to generate appearance of movement). Incidentally, if you wanted to change movement (i.e. direction of flag blowing on a shelter etc. I think an action could be used to do that)

Again, this is just my interpretation based on spell description and how I represent 'images' in this context.

Answer 3

It is, after all an image. Therefore, by definition, it is completely stationary and unchanging while you are not using your action to move it. You can, however, use your action to move it to the same location where it was before, and making the flames flicker once "naturally".