[toni-a]

After learning it the hard way,  now I have at least two backups of each photo.
one is on a standard hard disk the other one is on a network hard drive 
https://www.wd.com/products/personal-cloud-storage/my-cloud-home.html
Since we have a lot of electricity problems I prefer offline hard disk to RAID
while the LAN hard disk should be very practical it isn't one main problem: I am using it via WIFI and my router doesn't seem up to the job, even loading thumbnails takes ages, and I mostly access pictures on my laptop/tablet in my bed.
so what wireless solution would you suggest ? would a high performance router solve the issue ?? which one (s) ?
also read about routers  with eSATA ports are they necessary  if I want to plug non LAN hard disks to the router ???

[you2]

A couple of things to consider:

First I don't know if you are in the linux world or windows world; but I use a a filesystem that has a strong checksum per block (zfs). I also use raid and zfs will repair bad data doing monthly scans (called scrubs). While bit error are not common (bad cables are the most common cause); sector remaps are not that uncommon (when a sector remap occurs the new sector will be all 0). Most disks (though seagate is extremely unfriendly); will show useful data if if you have smart enabled.
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Off line disks will not 'remember' data forever. You didn't indicate if this is a hard disk or ssd; but either way you should probably verify the data once a year (an alternative to off line disk is a large usb stick - but likewise it will not remember data forever).
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As to your viewing issue there are too many unknowns. First it would be helpful to know the t-put (bit rate) of your transfer both when using the disk on your system and using it via wifi. Second one needs to understand if the bottleneck is the drive, router or device. Also if this is cloud storage then the problem could be latency between you and the cloud source - i think from the description it is a hard disk on your pc. Other issues could be that the device and router are fine but the distance from your bedroom to router is sufficient to cause issue or there is a barrier (metal wall, floor, ...) hindering the wifi signal. Most phones will allow for a wifi analysis app device that will test bit rate, show packet loss and signal strength. 
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This link will show you the various wifi bit rates:
https://www.intel.com/content/www/us/en/support/articles/000005725/network-and-i-o/wireless-networking.html
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While you can upgrade your router it won't help if your wireless device does not support the faster bit rates. Also the frequency that support faster bit rates tend to have shorter range and more prone to interference. 
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There is a lot of variance in transfer rate by a mechanical drive; but 200 to 400Mb/s should be feasible. 
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802.11n or 802.11ac should get you there if your device supports it and the distance between your device and router is reasonable (couple of rooms away; same floor). 
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Naturally if your device is old it might not be able to read/process the data that fast. Last but least if your device has limited memory it might be running into memory issues which would  make it very slow.

[toni-a]

I am in windows environment, in fact it's the router that is slowing the whole process, that's why I intend to get a new one.
The router has also a modem, its processor is very slow, if internet is used while streaming speed drops greatly. To non usable lebels around 100k per second

[wim]

I am in windows environment, in fact it's the router that is slowing the whole process, that's why I intend to get a new one.
The router has also a modem, its processor is very slow, if internet is used while streaming speed drops greatly. To non usable lebels around 100k per second

Hi toni-a,

Is that 100k bits or bytes?

Basically, I'd suggest a separate modem to a router, as that way you will likely get rid of the modem bottleneck/internet speed bottleneck (if appropriate), and you can set up a much safer network.
Also, WiFi is never faster than cabled network, provided you have at least 1 Gb network cabling (Cat 6, although Cat 5E comes close I guess). Do note that with WiFi, on your home network you're still bound to the connectionspeed between router and "cloud" storage, so if that is less than 1 Gb, it will feel slow especially with larger files. 1 Gb roughly equates to 100 kB (bytes) when transferring stuff etc., BTW. In addition, processing power of add-on cloud storage, especially the non-business oriented ones, tends to be so-so. You may actually be better off with a couple of external SSD disks, like the Samsung T5s. More expensive, but small, fast and easy to carry around.

As to a decent router, persoanlly I always recommend NetGear stuff for home use. Unlike other network equipement, NetGear stuff has never let em down. You could go for more industrial type equipment, but it gets very expensive very rapidly, but it is not faster, just has slightly more powerful transmitters, and hence larger penetration, plus the capability to deal with multiple connections a little easier at once.

If you'd like some recommendations of specific gear, let me know, I'll gladly help out.

Anyway, my 2.5 cents .

Kind regards, Wim

[toni-a]

Yesterday I got Linksys XAC 1200 the router and modem are two different units.
Will install it tonight and see how it works. Will keep you updated