Apple has released a new photo storage app for Macs, which can automatically store full-resolution images online.
The iCloud Photo Library syncs photos across devices while managing storage.
Users can opt to keep original high-res photos in the cloud with lower-res version on a Mac, PC or iOS device.
But critics highlight recent online photo security breaches and say Apple's storage fees are much higher than some of its competitors.
The iCloud Photo Library app responds to how much storage is left on each device.
It automatically downgrades the resolution of images held on a device as its storage space starts to run out - starting with the oldest images first - while ensuring they are still of suitable quality to be viewed full-screen.
If the user has a data connection and has chosen the online storage option for their full-res images, the app will download the larger original file as and when they need it. This could be for editing, zooming into the photo or for printing, for example.
Some experts wonder whether Apple's users are ready to trust the company with their photos after about 500 private pictures, mainly of celebrities, were stolen from the iCloud platform by hackers last year.
Apple later explained that this had happened as the result of a targeted attack in which the intruders had successfully obtained or guessed users passwords to its service, rather than hacked the platform.
Last October, Apple issued another security warning to its iCloud users, saying: "We're aware of intermittent organised network attacks using insecure certificates to obtain user information." It said its own servers had not been compromised.
Martin Garner, mobile services expert at CCS Insight, said: "People are sharing enormous trust when they use services like these. It's not just Apple - many other providers have also suffered breaches recently. But users will need to think about security and accessibility."
'Keep an eye on prices'
Many online storage providers offer cheaper plans for the same or more data to be stored online than Apple's iCloud.
However, each offers different functionality regarding how it syncs with devices, and whether it works automatically or needs user intervention
Apple iCloud compared with other online storage providers
The iCloud Photo Library is the first to keep a lower-res image on the device while sending the original full-res image to the cloud.
Unlike a simple back-up or copying of photos, this means users can keep the images on their devices while maximising storage space.
However, many consumers may still prefer deals such as Amazon's "Unlimited Photos plan", which would cost a fraction of the price to maintain a large library.
"Apple will have to keep an eye on prices as the market in online storage is extremely competitive," said Mr Garner.
"Many of its competitors, like Dropbox, have apps available on the iPhone, so it needs to be wary that users do have a good amount of choice.
"Some services like Microsoft and Amazon also bundle online storage with other services like software subscriptions or movie streaming, so Apple may need to consider doing likewise."