1) Заходи как-нибудь, покажешь фотки! {Imperative + Future}
I'm assuming this phrase means "come and show me the photos sometime". In English, both "come" and "show" are in Imperative, while in Russian it takes the form of "Imperative + Future".
I wonder if "Заходи, покажешь X" is the construction commonly used to express the idea of "come and do something". Do the following alternatives sound odd?
2) Заходи как-нибудь, покажи фотки! {Imperative + Imperative}
3) Заходи как-нибудь показать фотки! {Imperative + Infinitive} -- similar to "come to show"
On another note: Is it unusual to use the perfective "зайти" here?
4) Зайди как-нибудь, покажешь фотки! {Perfective Imperative + Perfective Future}
{vs}: Заходи как-нибудь, покажешь фотки! {Imperfective Imperative + Perfective Future}