Yes you could write that query as follows:
SELECT photos.* FROM user, photos WHERE zip IN (".$zips_in_range.") and photos.userid = user.userid
Note, this will only work the same if every user has a photo. If some don't then you'll need to adjust it to use a different sort of join and pull the UserID off the user file.
EDIT Of course, your database structure seems a little off from my point of view in any case.
e.g. if your photo table stores ALL the photos on your site then it's your users who should have a PhotoID column on their table, not the other way about, since presumably other tables may have photos associated with them and you shouldn't have a column for each possible linking table on the photo table.
On the other hand if your photo table is only storing a photo that a user has and each user only has one possible photo then why are they on a separate table at all? Just add more columns for each user to include that data?
Finally if you want to have one-to-many relationships or maybe many-to-many with some photos being used on multiple users and/or users having multiple photos, the correct method is not to store the foreign key of either table on other. Instead you create a photo_to_user table with a key that's UserID and PhotoID, containing only those fields and you then use it to link between the two to pull the appropriate records.