I figured I'd try and post a walkthrough ASAP to make it easier for anyone who is trying to unlock all the CGs and reach all the endings :3 It's relatively easy to get everything in this game anyhow.

PLEASE BE AWARE THAT BOTH SECTIONS CONTAIN SPOILERS FOR THE STORY!

- CGs - 

CG 01a: [The Cliche (female Volkham version)]

CG 01 A & B share the same slot in the gallery, but are unlocked at different times. A is unlocked at the beginning of the game, and B is unlocked in 2 out of 3 endings. To unlock this one, simply choose to have female Volkham (pink hair) as your partner at the start of the game.

CG 02a: [The Cliche (male Volkham version)]

The same as above, only choose to have male Volkham (brown hair) as your partner at the start of the game.

CGs 03 A & B, 04 A & B, 05 A & B and 06 A & B: [Bite Me]

Will all be unlocked automatically as the story unfolds, no matter what choices you make. To get 03 A& B, make sure you are playing as male Shearsmith with female Volkham. To get 04 A & B, make sure you are playing as female Shearmsith with male Volkham. To get 05 A & B, make sure to be playing as male Shearsmith with male Volkham. To get 06 A & B, make sure to be playing as female Shearsmith with female Volkham.

CG 01b: [Gotcha (female Volkham version)]

Make sure to have female Volkham as your partner and either select at least 1 choice on the right side of the screen (the ones that are generally more rude or confrontational) OR select all choices on the left side of the screen, and then reject Volkham's proposal.

CG 02b: [Gotcha (male Volkham version)]

The same as above, but make sure to have male Volkham as your partner.

CG 07: [Welcome Back! (female Volkham version)]

Make sure to have female Volkham as your partner. Make sure to pick all 5 choices on the left side of the screen (the ones that are generally kinder) and then accept Volkham's proposal.

CG 08: [Welcome Back! (male Volkham version)]

Same as above but make sure to have male Volkham as your partner.

- Endings -

'True' End

Make sure to select at least 1 of the choices on the right side (the ones that seem more rude/confrontational).

'A Grave Mistake' End (this is probably the worst one!)

Make sure to select all the choices on the left side (the ones that seem kinder) and then reject Volkham's proposal.

'Turned' End

Make sure to select all the choices on the left side (the ones that seem kinder) and then accept Volkham's proposal.