[Nightedge]

In informal situations could I write this?

-Let's wish his photos and film survive four years of traveling.

using the bare infinitive rather than the simple past tense.

[susan53]

You've got the wrong word - hope, not wish.

Hope = a mental desire for a future event to occur :
I hope John arrives soon
I hope the glasses survive the journey.

As hope already tells you that the event is future, it makes no difference whether you mark the following verb for futurity or not. You could also say eg ...
I hope John will arrive soon
I hope the glasses will survive the journey.
... but it's not necessary.

Wish = a mental desire for a present situation to be different. It is therefore a hypothetical statement - the real present situtaion is different - and a second form verb is therefore used. Eg :
Present situation = I don't have enough time to do things properly
Hypothetical statement = I wish I had more time

Present situation = I can't go to the sea this year
Hypothetical statement = I wish I could go to the sea this year

Present situation = I feel awful
hypothetical statement = I wish I didn't feel so awful

It has nothing to do with the level of formality - the two words have different meanings.

[Nightedge]

Excellent answer. Thank you. I especially like definite-sounding words like 'wrong', which I hope you can use more often in the future.

[susan53]

Unfortunately, when you're talking about language use it's rarely possible. Of course, language learners make errors that are right/wrong in the sense of being grammatically or lexically not possible - but most of your questions (apart from this one) are not about clear cut issues like that. Once you start looking at the use of language by proficient language users, 101 issues come into play - context, style, relationship between the interlocutors, regional differences etc etc etc.

[Nightedge]

Excellent answer. Thank you.

Your point is well taken.