Would any virus be transferred to my iPhone if I connect it to my laptop (with virus) via a USB cable in order to transfer some photos from my laptop to my phone?
No, highly doubtful it could.The software and OS is completely different between the two devices.Photo transfers to the phone are handled by the iTunes syncing process. The virus could hijack this process and inject it’s payload that is crafted for iOS. But there would have to be a pretty serious zero-day security flaw in how the phone and the syncing services on your computer work.But even if it could transfer it’s payload, the iPhone won’t accept any executable code without the correct digital signatures anyways. And apps don’t have root or direct system access anyways.Nothing is really impossible, but I believe the difficulty would be too high for this type of attack. There would have to be just the right combination of serious zero-day security flaws in a number of different systems to pull this off.
Does resetting a smartphone remove all the viruses and malware?
It mainly depends on the operating system (majority smartphones is using Android) and the virus/malware which infected the device and how deep it is buried in the system.Here there is explanation of the partitions on the Android system:Android Partitions Explained: boot, system, recovery, data, cache & miscAndroid partitions explainedCommon Android malware installs itself to /data partition where user has access to install the applications. That is what factory reset is capable of wiping.If malware manages to escalate it’s privileges to root (jailbreaking | rooting | misusing unlocked boot | fake rooting/jailbreak guide to guide users to install the malware) and install itself to /system partition or even to the /boot and|or /recovery partitions (which are normally not even visible to the phone users) then factory reset won’t help you and you would have to use some special tooling to get rid of the malware. I mean techniques like hardware re-flashing of the memory chip or re-gaining the root privileges and re-flashing the affected partitions from clean image/backup.There is also worth mentioning that quite significant number of (low-cost) Android devices was recently found to be shipped to customers with the malware pre-installed in the system so factory reset would not help in these cases.
If I transfer files from my laptop to my iPhone 6s, will the virus (given that there is) from my laptop transfer to my iPhone?
No. I will assume you're using windows. So, can you run the same apps on your computer as on your phone? I didn't think so. You can, however, infect other windows computers if it attaches to a USB drive. Viruses usually don't spread across multiple operating systems. In fact, a virus made for windows vista might not work with 7 or 8. Get avast and clean your computer. Also, stop visiting questionable porn sites and downloading everything you see.
If I back up my iPhone into iTunes, will it transfer any bugs or viruses into the computer or another iPhone I choose to restore?
Bugs are typically written for a particular Operating System (iOS or Mac OS X, for example). That means the programming behind them does not transfer across operating systems by design. Those who code malicious software would not invest much time writing a program that is just waiting on you to connect devices. Is it possible? Always, but I have not heard of it happening to anyone. Most malicious software travels socially, via social media, email communication, or file transfers between you and the Internet; this is not typically seen between your device and an application on your computer. For example, syncing between devices and Dropbox is generally safe, but syncing between open sources would be like playing with a live wire.To answer your question more directly, if the bug is inside of one of the applications you have on your iPhone, you will most certainly put the buggy app right back onto any iPhone you restore the backup to. If you don't run the buggy app on your Mac, it doesn't matter. Think of it as a light-switch; it waits for you to act before the electrical current runs its course.
Can an iPhone or iPad back up have a virus?
Per Google, the definition of a computer virus: "a piece of code that is capable of copying itself and typically has a detrimental effect, such as corrupting the system or destroying data." It has to interact with the software itself to change the way it runs, and programs on iOS, the system run on your iPhone or iPad, don't do that. They aren't allowed to. The only exception is if you have jailbroken your device, and few normal users seem to do that.Your backups usually don't even contain your operating software, but even on the off chance they do, they cannot contain a virus because of how iOS itself works. It may look like you have a "virus" on your device if Safari is infected with malicious cookies and won't navigate away from a site trying to tell you that you have a virus. To fix that issue, force quit Safari then clear history & website data from Settings > Safari, and that virus popup will go away. That is called a browser hijack and it is contained within the Safari app until it is gotten rid of.Thanks for the A2A.