Lol, it's hard but not impossible. ;)

yeah 1 has a scar on their forhead,
the other 1 doesnt't
also James has brown hair,
Harry has black
x

Oh, I thought James had black hair too

Also, apparently Lily's hair was a darker shade of red

i find it easy, james has no scar and lily has never been on a quiddtich team and many harry/ginny pics involve them both in qudditich robes eg this one. and james has black hair

It annoys me when they look the same... I mean, Lily had a completely different hair shade to Ginny!

nononononono James has BLACK hair. Trust me, I know,

Well, It's kinda hard but if you know your HP trivia you'll know. Harry has green eyes and a scar, and his dad doesn't, and like someone before me said, you will never see Lily in a quidditch outfit. As well as the fact that Lily has dark red hair as opposed to Ginny who is described with fiery red hair.

No stands for Harry and ginny yes is Lily and james because no has a scar on its head

I agree with owanalilypotter

i think its easy

it depends on the picture but most of the time i can

Yes. A true Potterhead can tell them apart :)

It's hard with fan art sometimes because the artist doesn't always make it clear

Like the pic for the "no" answer is Lily and James, but the pic for the "yes" answer could be either lily/james or harry/ginny

i agree, mostly it is drawn badly or wrongly (according to the book) if you cannot tell.
the differences like eyecolor, scar, clothes [i mean 70s/90s... hello, drawers -notice!], shade of haircolor and also facial expressions... i would claim that james looks much more convinced of himself when he is with lily as harry does when he ist with ginny... thse are not so insignificant that you could not tell them apart if you know the characters and the fanart is nicely drawn (and also the drawer has an apropriate knowledge of the books.

agree with Dissendium

Look for the scar... also Ginny usaully has more freckles! Also I think the Yes pic is Harry and Ginny... the scar is just visible

Unless there a scar or green eyes. The no pic is of HG, theres a scar and green eyes if you enlarge it. The yes pic could be either but look more like Ginny though.

well harry has the scar.and james don't

As long as the artist isn't a failure then I can tell, Lily looks completely different from Ginny and Pictures of Harry always have a scar and James doesn't

lily had deep red hair and stunning green eyes. Ginny has bright red hair and freckles with quidditch robes. James is usually drawn a lot more laid back and cocky looking with Lily just looking super annoyed. I personally think Lily and James are 653654364364 times cooler than Harry and Ginny. Lily is infinitely a better character than Ginny

Most of the time I can but it really depends on the picture I'm looking at.

Most of the time. And about the quidditch thing, Lily could be wearing James's jersey though ;)

It depends if it's well drawn or not

It ought to be easy to differentiate, but it does also depend on the detail of the fanart and whether the artist has considered the potential confusion and tried to differentiate.
1. Lily has darker red hair than Ginny and also has green eyes while Ginny's are brown.
2. Harry has green eyes while James' eyes are hazel, and Harry obviously has the scar.
3. Ginny is more likely to be shown wearing Quidditch gear, though Lily could possibly be shown wearing James' robes in a "borrow your boyfriend's jacket" type scene.
4. If they're pictured wearing Muggle clothing, Lily and James would be wearing older styles.