Author Topic: White Screen and other image issues directly linked to image uploading  (Read 384 times)

Offline TelePlay

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Over the past few years, several problems have been discovered all related to uploading images on/to the forum.


1)  Large Image Files would lock up a topic requiring Administrative Level Access to delete the offending reply containing the image. The allocation of system resources was increased to prevent topic locking. This locked topic was corrected by way of a software allocation patch and has not appeared since that patch was put into place - been fixed.


2)  Externally Linked Images posted to the forum since its beginning have been lost due to Picasa moving its images into Google Photos and recently PhotoBucket blocking images to external linking unless annual membership dues are paid for each account. There have been other externally linked images lost from other sites for various but similar reasons - broker URL links. As such, any images to be displayed on this forum must be done so by attaching them to a topic or reply. Six (6) images are allowed per topic or reply. If more than 6 images are to be uploaded, a second or third etc. reply can be created.


3)  All uploaded images are subjected to an Extensive Security Scan which might find suspicious code within the image and if so may result in a "security error" message on your screen. The best advice right now is to just upload reasonably sized images (see #4 below) and over 99.6% of the time they will pass the security scan and be uploaded to the forum. If, however, you do encounter a "security error, " the image will have to have its meta data removed and/or be resized a bit to eliminate the suspicious code. More on this can be read in a forum detailed discussion should it occur.

     Again, almost all images of reasonable size will upload without raising the "security error" issue. If you have one or more of these "suspicious" images and do not know how to remove the meta data, you can read how to do it at the BatchPurifier Lite forum topic or send me a PM and I will help you. Chances are you will never encounter the "security error" when uploading reasonably sized imaged.


4 a)  Large Image Files will cause the computer display to stop showing only the browser tool bars at the top of the screen (example attached below). The uploaded image and text do not appear. This is due to trying to upload an image file that is greater than 3 MBytes in size. It has always been highly suggested that anyone uploading an image make sure that it is no more than 3,000 pixels on its largest size (at 72 dpi) and the image file size not exceed 3 MBytes in size. 1,500 is good resolution for general photos and up to 3,000 work better for close up images filled with details (wiring, mechanical, etc).

        An image with its largest side being 1,500 to 3,000 pixels and saved in the jpg format at 72 dpi will be under 3 MBytes in file size and still have sufficient resolution to provide a high quality thumbnail which when clicked on will enlarge to show very good image detail.

   b)  It is the responsibility of the posting member to crop and/or reduce the size of an image so that it is under 3 MBytes. Failure to do so may result in the "white screen" due to the system running out of now more than sufficient allocated resources for image processing. The image screen load stops when it fails to complete image processing due to it's large size.

   c)  If that happens (you get a while screen when uploading an image), the only solution is to click on the browser "back" arrow, refresh the screen (F5), and attached a smaller version of the image that caused the white screen. Only the uploading member can recover from the "white screen" by going back one page and replacing the large image with a smaller version of that image. No exceptions - moderators can not help a member recover from a "white screen" other than writing his long paragraph.

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Anyone needing any help cropping and/or resizing images can send a Personal Message (PM) to me and I will help you edit an image.
« Last Edit: December 30, 2017, 12:51:26 PM by TelePlay »
            John . . .

              

Offline TelePlay

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Re: White Screen and other image issues directly linked to image uploading
« Reply #1 on: February 16, 2018, 10:37:45 AM »
GLOBAL MODERATOR POST


DIGITAL IMAGES    

( . . . why the “white screen” error occurs and how to prevent it )


Smart phone and digital camera images are taken at 72 dpi (dots/pixels per inch).

A 12 MegaPixel (MP) camera captures images that are 4,034 x 3,032 pixels in size (4034 x 3032 = 12,231,088 pixels (12.3 MP).

At 72 dpi, a 12 MP image takes a 56 inch by 42 inch image (4,034/72 = 56 and 3,032/72 = 42).

Each pixel is 1 byte (8 bits) in depth when images are taken in grey scale (black and white).

The total file size of an image taken in grey scale with a 12 MP camera is 4,034 x 3,032 x 1 = 12,231,088 bytes or 12.2 Mbytes.

Color images taken in RGB require 3 bytes in depth, 1 byte (8 bits) for each color.

The file size of a color image is therefore 4,034 x 3,032 x 3 = 36,693,264 bytes or 36.7 Mbytes.

When taking a photo with a 12 MP camera in RGB color, the captured image is 56 inches by 42 inches and 36.7 Mbytes in file size.

When an image is saved in the jpg format (as it is on the camera device), the image is compressed so the total raw file sizes stated above will become considerably smaller. A 36 Mbyte image will be saved on the camera as a compressed jpg image with a file size of 2 to 3 Mbytes depending of the color content of the image (more colorful images do not compress as much as less colorful images).

When opening the compressed camera image in an image processing software program such as PhotoShop or PhotoShop Elements, the “raw” or full sized, uncompressed file will be 36 Mbytes. A 56 by 42 inch image provides the ability to crop an image for contest without loosing resolution, the cropped images will still need to be reduced in size (3,000 pixels or less on the largest side) before being saved and attached to a post/reply.

The forum software examines and recodes each image being uploaded. If the image is greater than 3 Mbytes in compressed (jpg) file size, the forum software will be handling a 30+ Mbyte image. To examine and recode the image, the server memory stack available for the processing will need twice that amount of memory to keep the original image and the processed image in memory until the image is cleared for uploading and the original image replaced by the recoded image. Or, when uploading an image that is greater than 3 Mbytes in compressed size, system resources will require over 60 Mbytes for processing each image being uploaded. The forum software processes all images attached to a file before passing the recoded images on to and attaching them to a post or reply.

Images that exceed 3 Mbytes in file size, in compressed jpg format, can overload the server and cause the “white screen” error requiring the screen to be refreshed using F5 or the screen refresh icon, the offending image removed and the reduced size images attached. Without doing a screen refresh, trying to upload the reduced size images will cause another error saying something about the file was already posted – the memory stack overflow did not go to completion so the initial acceptance code does not know the post/reply was not saved.

Ways to avoid this problem:

1)   Before attaching the images to a post/reply, open the images in a image processing software and rotate, crop and reduce the size of the image to under 3 Mbytes before uploading.
2)   Take images with the camera set to a lower resolution (setting a digital camera to 3,264 × 2,448 resolution which is the same as an 8 MegaPixel camera) will allow jpg images to be uploaded as taken without issue).

There is no way around the problem caused by trying to upload images directly from a 12 MP camera. The forum software can be set to summarily reject any attachment greater than 3 Mbytes in size. This was tried and members complained loudly that the setting prevented attaching zip and pdf files which can easily exceed 3 Mbytes in file size. The limit was removed and the responsibility of processing images (using an advanced PC software program such as PhotoShop/Elements or more pedestrian image processing programs such as or similar to IfranView or MS Paint, or on a MAC, Preview, Photos, GIMP, Pixlr Editor, Fotor Photo Editor or anything else that allows the used to reduce the size of an image) before uploading (rotating, cropping and resizing) on the member’s plate. Failure to reduce an image to 3,000 pixels on the largest side or about 3 Mbytes in files size may cause the “white screen” error and the headaches of backing out of that error condition.

In the end, or as it now and how it will be going forward, it is the sole responsibility of the member attaching an image to a post/reply to process the images, to reduce their size to under 3 Mbytes, to avoid the "white screen" error.

            John . . .

              

Offline Doug Rose

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Re: White Screen and other image issues directly linked to image uploading
« Reply #2 on: February 16, 2018, 01:18:00 PM »
I got a new camera and could not post.  John worked with me and now it is working perfectly.

Setting of 3264 x 2448 worked for me....Doug
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