[FR]: Showing a placeholder for images could be improved

[larsen0815]

Brief description of the feature request

Two days ago, I noticed the following which I wasn't able to reproduce today. Still documenting it here in case this pops up for me or someone else (or you actually find a bug just looking at the code ;-) ):
When I go to the next article, the headline is shown immediately, but the image from the previous article is still shown for some milliseconds. When it has been loaded once, switching between articles also shows the image immediately.

Today, instead of the aforementioned, I noticed a placeholder image that is shown while the real image loads. So, after some milliseconds, the placeholder is instantly replaced by the final image which I find a little bit disrupting (going through multiple articles in quick succession).

Instead of using a placeholder, IMHO it would be better to just show an empty area. The text would not jump to another place when the image has been loaded, and there would not be a "show the placeholder only for some milliseconds". If there is an error on loading the final image, the placeholder could still be displayed afterwards in such cases.

Log:

time="170218.578" type="debug" -> gui: Current row changed - proxy 'QModelIndex(71,6,0x1c834df0540,MessagesProxyModel(0x1c832509d50, name = MessagesProxyModel))', source 'QModelIndex(71,6,0x0,MessagesModel(0x1c82f51eaf0))'.
time="170218.578" type="debug" -> gui: Marking article as read immediately.
time="170218.579" type="debug" -> database: SQLite connection 'RecycleBin' is already active.
time="170218.579" type="debug" -> database: SQLite database connection 'RecycleBin' to file 'C:/Users/lmonsees/AppData/Local/RSS Guard 4/database/database.db' seems to be established.
time="170218.579" type="debug" -> feed-model: There is request to reload feed model, reloading the 1 items individually.
time="170218.581" type="debug" -> gui: HTML image resizing took 0 miliseconds.

"Enable external resources" is enabled.
btw: Typo in "miliseconds", should be "milliseconds"