Inconsistent success rate on nls.co.uk site

[JohnDeZoom]

I've successfully obtained one image from the maps.nls.uk site by typing in this link:

http://maps.nls.uk/imgsrv/iipsrv.fcgi?iiif=/10110/101103608.jp2/info.json

into the DeZoomify window, but with another one, this .....

http://maps.nls.uk/imgsrv/iipsrv.fcgi?iiif=/10234/102344075.jp2/info.json

I get an error ....
"NS_ERROR_FAILURE
(http://ophit.alwaysdata/dezoomify.net/zoommanager.js:62)"

I've checked and the tile from which I formulated the address exists and displays.

The second link is derived from the tile links for:
http://maps.nls.uk/view/126524075

What exactly is this error message related to ? and Any idea for this inconsistency ?

Thanks
John

[JohnDeZoom]

The message precisely is:

[lovasoa]

Dezoomify FAQ item explaining how to allocate more memory to large canvases

Did you try allocating more memory to canvas as specified in the FAQ ?

[lovasoa]

I have gfx.max-alloc-size set to 2000000000 and dezooming your image works for me (firefox 53.0.2 64 bits on linux).

[lovasoa]

Here it is:

low resolution

full resolution

280Mb png file

[JohnDeZoom]

Thank you. That did the trick although on my machine (4Gb memory) it's a trifle slow !
I tried first doubling the memory to 1000000000 without success burrrìt 2000000000 worked (slowly).
It did crash the machine the first time becasue I had other thngs running. I was a bit surprised becasuìse the file I had managed to download was 250Mb and took nowhere near as long to process. I guess it's a case of experimenting the best memory setting for any particular computer

[JohnDeZoom]

oh and is it possible to generate the downloaded files in .jpg format directly ? I also noticed the x10 file size saving by converting to jpeg afterwards.

[lovasoa]

If you don't have a lot of memory on your computer, then you'd better set back the property to its old value, or any website will be able to crash your browser of it wants to. It's not possible to export the file in JPEG, and dezoomify cannot do anything about that. Firefox exports to png. Also, please note that converting from PNG to JPEG doesn't preserve the quality of the image. PNG is a lossless compression format, while JPEG is lossy.

[JohnDeZoom]

message about the jpeg possibilities understood. For my uses jpg is fine but I understand you can't get anything but png becasue that's the source. Thanks for your explanation anyway

[JohnDeZoom]

what do you mean any website will be able to crash my browser IF IT WANTS TO ?? !!!!!
Also, by 'setting it back' - to what ? Originally there wasn't the keyword present so I suppose you mean delete the keyword previously created ?

[JohnDeZoom]

UPDATE - after being able to get the quoted image by increasing the parameter to 2Gb, I then tried this one:-
http://maps.nls.uk/imgsrv/iipsrv.fcgi?iiif=/12652/126522371.jp2/info.json
but got nothing but freezing on 1%.
I tried to increase memory further but I could only increse to 2.1Gb, anything more attempted resulted in a refusal by Firefox to do so ('invalid number' was the error message when I tried).
I have 4 Mb so I'd have thought I could increase it more than that.
Do you know how Firefox works in rìthat respect ?
I assume that this image is just too big , could I ask you to download it and post the jpg version here please, or just tell me what the image size actually is, for reference ? Thanks