I'd be very leery about the simpler figment spells, like Silent Image. It creates a purely optical illusion, and thus, if you use it to create something that normally produces sound, heat, smell etc., I'd grant a hefty save bonus at the very least. Consider the primary senses of your opponents in this.
Against creatures relying on sight a lot (like humans, or maybe eagles), Silent Image is probably quite useful. Against a pack of wolves? I don't think so. You'd need a Major Image in my game: wolves rely on hearing AND smell to a very great deal, probably more than we humans can even imagine. So forget purely optical illusions. A wolf might be startled by it, but when its blood is up and real prey with real bleeding wounds are already present, it would likely ignore the image completely. The same is true for most big predators.
Another thing to consider is what you use your spell to imitate. Your best bets might be other spell effects, especially against seasoned veterans without much formal spellcraft training. Your image may easily look like a summoning spell to them, or whatever else. Best yet: mix in real summonses with illusions...
The aforementioned Obscuring Mist or stone wall is another favorite, since it works in its obscuring function as long as the other side doesn't make its save, and your group can train this tactic beforehand. Like Tiny Hut, but cheaper in spell slots.
All in all, I'd say Silent Image is given too much credit on CO boards: yes, it's flexible, maybe the most flexible spell in 1st level. But it also requires concentration, it's small and anchored in place, and the limitation in affected senses really puts a dent in its usefulness in a lot of circumstances. At the latest after 7th level or so, the spell really peters out, while Major Image remains useful for a looong while after. As do some other 1st level spells, btw, like Identify, Mage Armor, Protection from Evil, Unseen Servant, True Strike, Enlarge Person, even Magic Missile. Silent Image is a very good spell, but lacks some important functions that only higher-level spells can supply.