I recently saw an image with animate objects (no people or people like) that were connected to each other, at first glance it seemed normal, but facial expressions were edited on to make it seem impure. Is looking at such images a sin?

Also if someone draws stick figures doing 'poses' is this pornographic?

What about when people make/say sɛҳuąƖ innuendos?

Always reject anything impure and you'll be fine. And don't seek it out of course. And when possible, show disapproval to others when they introduce such garbage to your eyes.

I struggle with vain curiosity, I don't really fall into lust when I see impure images, even when I am out in public if I see a women's rump in inappropriate clothing then I might think/feel in my mind the word 'nice' but I don't feel lust if that makes sense.

If you struggle with vain curiosity, then you should not just randomly look up things on the internet. Every time you want to go look at something, say a prayer instead.

Good you don't lust, bad you give into vain curiosity, which distracts you from your duty of state.

Other then work and prayers I don't really have much to do as a single guy 

Those are not a sin yet, but they can lead to sinful thoughts and desires if you keep on playing with it or let it increase your curiosity to look at actual impure images. if you continue to look at these silly images voluntarily, now that you know it bothers you, then you will be putting yourself at risk for a fall into sin. God has given you the grace to see that this is a trap, take the warning and move onto something productive.

Would it be a mortal sin if the impure image would be hardcore porn if it was people instead of inanimate objects?

Other then work and prayers I don't really have much to do as a single guy

Then maybe you need to find a hobby?  Something to do away from work and praying, that is not on the internet.

Yes, you voluntarily seek and look at those images, But, if by accident or curiosity you take a peek to see if it was really porn, then no, but once you realize what it is, you must turn away. If your body begins to feel pleasure, then you must not consent and make an active motion to look away and reject such images. But you keep putting yourself in occasions where you will be exposed to these images, then it will be a sin.

For you, use the internet very little and only for specific websites for a specific purpose, no web surfing.

Well put!

Yes, you voluntarily seek and look at those images, But, if by accident or curiosity you take a peek to see if it was really porn, then no, but once you realize what it is, you must turn away. If your body begins to feel pleasure, then you must not consent and make an active motion to look away and reject such images. But you keep putting yourself in occasions where you will be exposed to these images, then it will be a sin.

For you, use the internet very little and only for specific websites for a specific purpose, no web surfing.

Don't internet browsers have filters that the OP could use to avoid these sorts of images?

I recently saw an image with animate objects (no people or people like) that were connected to each other, at first glance it seemed normal, but facial expressions were edited on to make it seem impure. Is looking at such images a sin?

Also if someone draws stick figures doing 'poses' is this pornographic?

What about when people make/say sɛҳuąƖ innuendos?

I think it's one of the things St. Paul condemns. What you are describing is vulgarity, St. Paul calls it "Scurrility." Scurrility is smutty conversations and jokes, where people reference obscene or sinful things, (usually sɛҳuąƖ) without actually saying what is meant, but everyone knows what is really meant. St. Paul tells us to have nothing to do with that.

Eph 5:1 Be ye therefore followers of God, as most dear children;  2 And walk in love, as Christ also hath loved us, and hath delivered himself for us, an oblation and a sacrifice to God for an odour of sweetness.  3 But fornication, and all uncleanness, or covetousness, let it not so much as be named among you, as becometh saints:  4 Or obscenity, or foolish talking, or scurrility, which is to no purpose; but rather giving of thanks.  5 For know you this and understand, that no fornicator, or unclean, or covetous person (which is a serving of idols), hath inheritance in the kingdom of Christ and of God.