Img Tab is the image browser of APT. It allows fast previewing and deletion of images. It has some features that are related to astro-photography. For example if you image in RAW+L quality mode APT will group the two files (CR2/NEF and JPG) to show one thumbnail. If you use the Delete button it will remove both files at once. When Preview mode is set to 1:1 the scrolled position will remain allowing to inspect same region in series of images.
Use Shift+Click on the Gear tab button in order to make the tab a floating window. Click on the "x" button or use Shift+Click to dock it back.
Preview Effects
Opens/Close the Preview Effects dialog box which allows applying various effects on the loaded image or LiveView stream. The saved images are not affected. If there is asterisk after "Preview Effect" it means that one or more effects are activated.
LV++
Tries to intensify the EOS LiveView stream. Note that EOS Histogram has LiveView auto-stretching option that can give better results. In CCD/CMOS mode the LiveView can be intensified by CCD Histogram stretching or auto-stretching
LV Stack
Stacks number of frames from the EOS LiveView stream. The count is configurable from Advanced settings tab
FlipHor
Flips the image horizontally
FlipVer
Flips the image vertically
Sharp
Applies sharpening filter
Negative
Makes the image negative
Gamma
Increases the gamma with +0.25 on every click till +3.00. Double-click disables the effect
Rotate
Rotates the image with +90 degrees clock-wise on every click. Double-click disables the effect
Brightness
Increases the image brightness with +25% on every click till +200%. Double-click disables the effect
Note that performance can get slow (especially on a weak computer) if you are using Preview Effects over big images in combination with Preview Modes "1:1" and "1:1 Scroll"
Controls the preview of the loaded image in the "LiveView / Image Preview" panel. It duplicates the functionality of the same control in Camera tab in order to save tab switching.
On (Fit)
Shows the image in the preview area after every exposure. The image will be scaled to fit in the area
Off
No preview
On (1:1)
Shows un-scaled part from the loaded image that fits in the preview area
On (1:1) Scroll
Shows scrolling buttons to select the image area that you want to see in mode “On (1:1)”. Use the central rectangle to view the center of the image
To scroll the image smoothly in “On (1:1)” or “On (1:1) Scroll” modes, hold the Shift key and drag with the mouse. You can also use the right mouse button to drag the image.
To switch quickly between “On (Fit)” and “On (1:1)” modes double click on the image. This allows to center the part of the image without scrolling.
If you double click on a scroll arrow, position will be moved to the corresponding border.
Enables/disables the Image Center Thumbnails (ICT) mode. The ITC mode shows in the thumbnail the center of the image in 1:1 scale. Is is very handful to evaluate the guiding quality without need to load and scroll the image. The bad images can be deleted easily with the Delete button.
In left is a thumbnail of the whole image, in right is the thumbnail of the image center.
It is possible to toggle both modes for one image only with right click on it.
List of thumbnails. Double click on image thumbnail loads the image in the "LiveView / Image Preview" panel. Click with the right mouse button toggles between full image thumbnail (in left image) and image center thumbnail (right).
Shift + Double Click loads the CR2/NEF/FITS image into the associated application.
Shift + Ctrl + Double Click loads the JPG image into the associated application.
Double click on folder thumbnail opens the selected folder and makes it current one.
If the setting "Hide folders in Image Browser" in Main settings tab is enabled, the list contains only image thumbnails. If the option is disabled the list will include also thumbnails for the sub-folders of current folder.
Sample folder thumbnail:
In the lower right corner of image thumbnail are printed image types (files) represented by this thumbnail The possible values are:
JPG
One file only in JPG format.
CR2 and JPG
Two files - CR2 and JPG formats
NEF and JPG
Two files - NEF and JPG formats
CR2, TIFF and JPG
Three files - CR2, TIFF* and JPG formats
NEF, TIFF and JPG
Three files - NEF, TIFF* and JPG formats
FITS
One file only in FITS format.
*TIFF file is generated when the option "Convert CR2/NEF to TIFF" option is enabled in the Advanced settings tab.
Note that changing the current folder in the Img Tab has not effect on the folder where the images are stored.
If the file is in FITS format opens the FITS Header viewer. The information in it is updated if other image is loaded. The shortcut for this dialog box is Alt+I.
Deletes the selected file (or files if the thumbnail represents more than one). The file(s) are moved in the Recycle Bin, so they can be restored in case you change your mind. You can use also the Del key of the keyboard.
Related videos: 
