add note to image-* plugin docs about animated gifs and render_on_canvas - fixes #1594

docs/plugins/jspsych-image-button-response.md

@@ -22,7 +22,7 @@ trial_duration | numeric | null | How long to wait for the subject to make a res
 margin_vertical | string | '0px' | Vertical margin of the button(s).
 margin_horizontal | string | '8px' | Horizontal margin of the button(s).
 response_ends_trial | boolean | true | If true, then the trial will end whenever the subject makes a response (assuming they make their response before the cutoff specified by the `trial_duration` parameter). If false, then the trial will continue until the value for `trial_duration` is reached. You can set this parameter to `false` to force the subject to view a stimulus for a fixed amount of time, even if they respond before the time is complete.
-render_on_canvas | boolean | true | If true, the image will be drawn onto a canvas element. This prevents a blank screen (white flash) between consecutive image trials in some browsers, like Firefox and Edge. If false, the image will be shown via an img element, as in previous versions of jsPsych.
+render_on_canvas | boolean | true | If true, the image will be drawn onto a canvas element. This prevents a blank screen (white flash) between consecutive image trials in some browsers, like Firefox and Edge. If false, the image will be shown via an img element, as in previous versions of jsPsych. If the stimulus is an **animated gif**, you must set this parameter to false, because the canvas rendering method will only present static images.
 
 ## Data Generated
 

docs/plugins/jspsych-image-keyboard-response.md

@@ -19,7 +19,7 @@ In addition to the [parameters available in all plugins](/overview/plugins#param
 | stimulus_duration     | numeric          | null               | How long to show the stimulus for in milliseconds. If the value is `null`, then the stimulus will be shown until the subject makes a response. |
 | trial_duration        | numeric          | null               | How long to wait for the subject to make a response before ending the trial in milliseconds. If the subject fails to make a response before this timer is reached, the subject's response will be recorded as null for the trial and the trial will end. If the value of this parameter is `null`, then the trial will wait for a response indefinitely. |
 | response_ends_trial   | boolean          | true               | If true, then the trial will end whenever the subject makes a response (assuming they make their response before the cutoff specified by the `trial_duration` parameter). If false, then the trial will continue until the value for `trial_duration` is reached. You can set this parameter to `false` to force the subject to view a stimulus for a fixed amount of time, even if they respond before the time is complete. |
-| render_on_canvas      | boolean          | true               | If `true`, the image will be drawn onto a canvas element. This prevents a blank screen (white flash) between consecutive image trials in some browsers, like Firefox and Edge. If `false`, the image will be shown via an img element, as in previous versions of jsPsych. |
+| render_on_canvas      | boolean          | true               | If `true`, the image will be drawn onto a canvas element. This prevents a blank screen (white flash) between consecutive image trials in some browsers, like Firefox and Edge. If `false`, the image will be shown via an img element, as in previous versions of jsPsych. If the stimulus is an **animated gif**, you must set this parameter to false, because the canvas rendering method will only present static images. |
 
 ## Data Generated
 

docs/plugins/jspsych-image-slider-response.md

@@ -26,7 +26,7 @@ prompt | string | null | This string can contain HTML markup. Any content here w
 stimulus_duration | numeric | null | How long to show the stimulus for in milliseconds. If the value is null, then the stimulus will be shown until the subject makes a response.
 trial_duration | numeric | null | How long to wait for the subject to make a response before ending the trial in milliseconds. If the subject fails to make a response before this timer is reached, the subject's response will be recorded as null for the trial and the trial will end. If the value of this parameter is null, then the trial will wait for a response indefinitely.
 response_ends_trial | boolean | true | If true, then the trial will end whenever the subject makes a response (assuming they make their response before the cutoff specified by the `trial_duration` parameter). If false, then the trial will continue until the value for `trial_duration` is reached. You can set this parameter to `false` to force the subject to view a stimulus for a fixed amount of time, even if they respond before the time is complete.
-render_on_canvas | boolean | true | If true, the image will be drawn onto a canvas element. This prevents a blank screen (white flash) between consecutive image trials in some browsers, like Firefox and Edge. If false, the image will be shown via an img element, as in previous versions of jsPsych.
+render_on_canvas | boolean | true | If true, the image will be drawn onto a canvas element. This prevents a blank screen (white flash) between consecutive image trials in some browsers, like Firefox and Edge. If false, the image will be shown via an img element, as in previous versions of jsPsych. If the stimulus is an **animated gif**, you must set this parameter to false, because the canvas rendering method will only present static images.
 
 ## Data Generated